Vulnerability-Lookup

CVE-2026-89649 (GCVE-0-2026-89649)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:45 – Updated: 2026-09-13 06:32

Title

ceph: bound xattr value length in __build_xattrs()

Summary

In the Linux kernel, the following vulnerability has been resolved: ceph: bound xattr value length in __build_xattrs() __build_xattrs() decodes the MDS-supplied xattr blob one attribute at a time. For each attribute it reads a 32-bit name length, advances past the name bytes, reads a 32-bit value length, records the value pointer, and advances past the value bytes. The two length fields are read with ceph_decode_32_safe(), but the value bytes themselves are advanced over with a bare "p += len" and no ceph_decode_need() check that "len" bytes remain in the blob. For every attribute except the last, the next iteration's ceph_decode_32_safe() on the following name length implicitly verifies that the previous value did not run past the blob end. The final attribute has no successor, so its decoded value length is never checked against the blob bounds. A malicious or compromised metadata server can set the last attribute's value length larger than the bytes actually present in the blob. The blob is a dedicated kvmalloc() allocation sized to the wire length (ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the oversized length in xattr->val_len verbatim, and a later getxattr(2) runs memcpy(value, xattr->val, xattr->val_len) into a user-supplied buffer, copying bytes past the end of the allocation back to user space. Impact: a malicious metadata server discloses adjacent kernel heap bytes to a local user via getxattr(2) on a CephFS file. Add the missing ceph_decode_need() so an out-of-bounds value length on the final attribute fails the decode and returns -EIO instead of being stored.

Severity

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/38be2f3c41ecaba58…
https://git.kernel.org/stable/c/1dd356310b1660215…
https://git.kernel.org/stable/c/b12b3320c81fd72ab…
https://git.kernel.org/stable/c/68d541754d6cd3bb9…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: 355da1eb7a1f91c276b991764e951bbcd8047599 , < 38be2f3c41ecaba58bb92dc16603e09ba9fd64f1 (git) Affected: 355da1eb7a1f91c276b991764e951bbcd8047599 , < 1dd356310b1660215f9a3626580bf8b363ef981e (git) Affected: 355da1eb7a1f91c276b991764e951bbcd8047599 , < b12b3320c81fd72ab36388fb2445fec9c3038f10 (git) Affected: 355da1eb7a1f91c276b991764e951bbcd8047599 , < 68d541754d6cd3bb98d1fd8314f57e5eb533557d (git)	guessed
Linux	Linux	Affected: 2.6.34 Unaffected: 0 , < 2.6.34 (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/xattr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "38be2f3c41ecaba58bb92dc16603e09ba9fd64f1",
              "status": "affected",
              "version": "355da1eb7a1f91c276b991764e951bbcd8047599",
              "versionType": "git"
            },
            {
              "lessThan": "1dd356310b1660215f9a3626580bf8b363ef981e",
              "status": "affected",
              "version": "355da1eb7a1f91c276b991764e951bbcd8047599",
              "versionType": "git"
            },
            {
              "lessThan": "b12b3320c81fd72ab36388fb2445fec9c3038f10",
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              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "355da1eb7a1f91c276b991764e951bbcd8047599",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/xattr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.34"
            },
            {
              "lessThan": "2.6.34",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: bound xattr value length in __build_xattrs()\n\n__build_xattrs() decodes the MDS-supplied xattr blob one attribute at a\ntime. For each attribute it reads a 32-bit name length, advances past the\nname bytes, reads a 32-bit value length, records the value pointer, and\nadvances past the value bytes. The two length fields are read with\nceph_decode_32_safe(), but the value bytes themselves are advanced over\nwith a bare \"p += len\" and no ceph_decode_need() check that \"len\" bytes\nremain in the blob.\n\nFor every attribute except the last, the next iteration\u0027s\nceph_decode_32_safe() on the following name length implicitly verifies\nthat the previous value did not run past the blob end. The final\nattribute has no successor, so its decoded value length is never checked\nagainst the blob bounds. A malicious or compromised metadata server can\nset the last attribute\u0027s value length larger than the bytes actually\npresent in the blob.\n\nThe blob is a dedicated kvmalloc() allocation sized to the wire length\n(ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the\noversized length in xattr-\u003eval_len verbatim, and a later getxattr(2) runs\nmemcpy(value, xattr-\u003eval, xattr-\u003eval_len) into a user-supplied buffer,\ncopying bytes past the end of the allocation back to user space.\n\nImpact: a malicious metadata server discloses adjacent kernel heap bytes\nto a local user via getxattr(2) on a CephFS file. Add the missing\nceph_decode_need() so an out-of-bounds value length on the final\nattribute fails the decode and returns -EIO instead of being stored."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The MDS-supplied xattr blob is delivered over the kernel Ceph messenger TCP session in inode replies (parse_reply_info_in \u2192 ceph_fill_inode) and CEPH_MSG_CLIENT_CAPS (handle_cap_grant), so a malicious or compromised MDS reaches __build_xattrs() with network protocol data.\nAC:L - The attacker fully controls the last attribute\u0027s 32-bit value length in the xattr blob; setting it larger than the remaining kvmalloc\u0027d wire bytes reliably records an oversized val_len with no race, special memory layout, or rare kernel config.\nPR:N - Exploitation requires only the ability to send crafted MDS replies or cap grants as the remote cluster peer on an established session; no local account, capability, or user-namespace privilege on the victim host is needed.\nUI:N - Once CephFS is mounted, MDS replies and cap grants are processed automatically, and ceph_get_acl()/__ceph_getxattr() run on ordinary inode permission checks and xattr queries without a further victim mount or click at exploit time.\nS:U - The out-of-bounds heap read, userspace disclosure, and possible oops remain inside the client kernel\u0027s own security authority and do not cross a VM, IOMMU, or other distinct trust boundary.\nC:H - __set_xattr() stores the oversized length and getxattr memcpy()s that many bytes from the undersized blob into a user buffer (up to XATTR_SIZE_MAX), disclosing adjacent kernel heap including pointers; the in-kernel ACL path can copy still larger extents.\nI:N - The bug is an out-of-bounds read into a destination buffer sized from the claimed length (VFS kvzalloc or ceph_get_acl kzalloc); it does not provide an attacker-selected write into kernel memory.\nA:H - An oversized value length that extends into unmapped kernel addresses faults the in-kernel memcpy in __ceph_getxattr() or ceph_get_acl(), causing a kernel oops or panic the MDS can trigger repeatedly."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:32:28.079Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/38be2f3c41ecaba58bb92dc16603e09ba9fd64f1"
        },
        {
          "url": "https://git.kernel.org/stable/c/1dd356310b1660215f9a3626580bf8b363ef981e"
        },
        {
          "url": "https://git.kernel.org/stable/c/b12b3320c81fd72ab36388fb2445fec9c3038f10"
        },
        {
          "url": "https://git.kernel.org/stable/c/68d541754d6cd3bb98d1fd8314f57e5eb533557d"
        }
      ],
      "title": "ceph: bound xattr value length in __build_xattrs()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89649",
    "datePublished": "2026-09-11T19:45:40.118Z",
    "dateReserved": "2026-09-11T19:38:34.742Z",
    "dateUpdated": "2026-09-13T06:32:28.079Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89649",
      "date": "2026-09-13",
      "epss": "0.00595",
      "percentile": "0.46562"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-13T01:04:49.000Z",
      "cve": "CVE-2026-89649",
      "id": "msrc_CVE-2026-89649",
      "initial_release_date": "2026-09-13T01:04:49.000Z",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "ceph: bound xattr value length in __build_xattrs()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89649.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89649\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-11T20:19:50.897\",\"lastModified\":\"2026-09-13T07:17:30.127\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nceph: bound xattr value length in __build_xattrs()\\n\\n__build_xattrs() decodes the MDS-supplied xattr blob one attribute at a\\ntime. For each attribute it reads a 32-bit name length, advances past the\\nname bytes, reads a 32-bit value length, records the value pointer, and\\nadvances past the value bytes. The two length fields are read with\\nceph_decode_32_safe(), but the value bytes themselves are advanced over\\nwith a bare \\\"p += len\\\" and no ceph_decode_need() check that \\\"len\\\" bytes\\nremain in the blob.\\n\\nFor every attribute except the last, the next iteration\u0027s\\nceph_decode_32_safe() on the following name length implicitly verifies\\nthat the previous value did not run past the blob end. The final\\nattribute has no successor, so its decoded value length is never checked\\nagainst the blob bounds. A malicious or compromised metadata server can\\nset the last attribute\u0027s value length larger than the bytes actually\\npresent in the blob.\\n\\nThe blob is a dedicated kvmalloc() allocation sized to the wire length\\n(ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the\\noversized length in xattr-\u003eval_len verbatim, and a later getxattr(2) runs\\nmemcpy(value, xattr-\u003eval, xattr-\u003eval_len) into a user-supplied buffer,\\ncopying bytes past the end of the allocation back to user space.\\n\\nImpact: a malicious metadata server discloses adjacent kernel heap bytes\\nto a local user via getxattr(2) on a CephFS file. Add the missing\\nceph_decode_need() so an out-of-bounds value length on the final\\nattribute fails the decode and returns -EIO instead of being stored.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/ceph/xattr.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"355da1eb7a1f91c276b991764e951bbcd8047599\",\"lessThan\":\"38be2f3c41ecaba58bb92dc16603e09ba9fd64f1\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"355da1eb7a1f91c276b991764e951bbcd8047599\",\"lessThan\":\"1dd356310b1660215f9a3626580bf8b363ef981e\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"355da1eb7a1f91c276b991764e951bbcd8047599\",\"lessThan\":\"b12b3320c81fd72ab36388fb2445fec9c3038f10\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"355da1eb7a1f91c276b991764e951bbcd8047599\",\"lessThan\":\"68d541754d6cd3bb98d1fd8314f57e5eb533557d\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/ceph/xattr.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.34\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.34\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.109\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H\",\"baseScore\":9.1,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.2}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1dd356310b1660215f9a3626580bf8b363ef981e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/38be2f3c41ecaba58bb92dc16603e09ba9fd64f1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/68d541754d6cd3bb98d1fd8314f57e5eb533557d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b12b3320c81fd72ab36388fb2445fec9c3038f10\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T07:00:00+00:00",
      "cve": "CVE-2026-89649",
      "id": "CVE-2026-89649",
      "initial_release_date": "2026-09-11T19:45:40.118000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ceph: Linux kernel CephFS: Information disclosure via out-of-bounds read in extended attribute handling",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89649.json",
      "version": "3"
    }
  }
}

FKIE_CVE-2026-89649

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-13 07:17

Severity

9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1dd356310b1660215f9a3626580bf8b363ef981e
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/38be2f3c41ecaba58bb92dc16603e09ba9fd64f1
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/68d541754d6cd3bb98d1fd8314f57e5eb533557d
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b12b3320c81fd72ab36388fb2445fec9c3038f10

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/xattr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "38be2f3c41ecaba58bb92dc16603e09ba9fd64f1",
              "status": "affected",
              "version": "355da1eb7a1f91c276b991764e951bbcd8047599",
              "versionType": "git"
            },
            {
              "lessThan": "1dd356310b1660215f9a3626580bf8b363ef981e",
              "status": "affected",
              "version": "355da1eb7a1f91c276b991764e951bbcd8047599",
              "versionType": "git"
            },
            {
              "lessThan": "b12b3320c81fd72ab36388fb2445fec9c3038f10",
              "status": "affected",
              "version": "355da1eb7a1f91c276b991764e951bbcd8047599",
              "versionType": "git"
            },
            {
              "lessThan": "68d541754d6cd3bb98d1fd8314f57e5eb533557d",
              "status": "affected",
              "version": "355da1eb7a1f91c276b991764e951bbcd8047599",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/xattr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.34"
            },
            {
              "lessThan": "2.6.34",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: bound xattr value length in __build_xattrs()\n\n__build_xattrs() decodes the MDS-supplied xattr blob one attribute at a\ntime. For each attribute it reads a 32-bit name length, advances past the\nname bytes, reads a 32-bit value length, records the value pointer, and\nadvances past the value bytes. The two length fields are read with\nceph_decode_32_safe(), but the value bytes themselves are advanced over\nwith a bare \"p += len\" and no ceph_decode_need() check that \"len\" bytes\nremain in the blob.\n\nFor every attribute except the last, the next iteration\u0027s\nceph_decode_32_safe() on the following name length implicitly verifies\nthat the previous value did not run past the blob end. The final\nattribute has no successor, so its decoded value length is never checked\nagainst the blob bounds. A malicious or compromised metadata server can\nset the last attribute\u0027s value length larger than the bytes actually\npresent in the blob.\n\nThe blob is a dedicated kvmalloc() allocation sized to the wire length\n(ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the\noversized length in xattr-\u003eval_len verbatim, and a later getxattr(2) runs\nmemcpy(value, xattr-\u003eval, xattr-\u003eval_len) into a user-supplied buffer,\ncopying bytes past the end of the allocation back to user space.\n\nImpact: a malicious metadata server discloses adjacent kernel heap bytes\nto a local user via getxattr(2) on a CephFS file. Add the missing\nceph_decode_need() so an out-of-bounds value length on the final\nattribute fails the decode and returns -EIO instead of being stored."
    }
  ],
  "id": "CVE-2026-89649",
  "lastModified": "2026-09-13T07:17:30.127",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-11T20:19:50.897",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1dd356310b1660215f9a3626580bf8b363ef981e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/38be2f3c41ecaba58bb92dc16603e09ba9fd64f1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/68d541754d6cd3bb98d1fd8314f57e5eb533557d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b12b3320c81fd72ab36388fb2445fec9c3038f10"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-J8WR-C6W3-J472

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-13 09:32

Details

In the Linux kernel, the following vulnerability has been resolved:

ceph: bound xattr value length in __build_xattrs()

__build_xattrs() decodes the MDS-supplied xattr blob one attribute at a time. For each attribute it reads a 32-bit name length, advances past the name bytes, reads a 32-bit value length, records the value pointer, and advances past the value bytes. The two length fields are read with ceph_decode_32_safe(), but the value bytes themselves are advanced over with a bare "p += len" and no ceph_decode_need() check that "len" bytes remain in the blob.

For every attribute except the last, the next iteration's ceph_decode_32_safe() on the following name length implicitly verifies that the previous value did not run past the blob end. The final attribute has no successor, so its decoded value length is never checked against the blob bounds. A malicious or compromised metadata server can set the last attribute's value length larger than the bytes actually present in the blob.

The blob is a dedicated kvmalloc() allocation sized to the wire length (ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the oversized length in xattr->val_len verbatim, and a later getxattr(2) runs memcpy(value, xattr->val, xattr->val_len) into a user-supplied buffer, copying bytes past the end of the allocation back to user space.

Impact: a malicious metadata server discloses adjacent kernel heap bytes to a local user via getxattr(2) on a CephFS file. Add the missing ceph_decode_need() so an out-of-bounds value length on the final attribute fails the decode and returns -EIO instead of being stored.

Severity

9.1 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-89649"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:50Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: bound xattr value length in __build_xattrs()\n\n__build_xattrs() decodes the MDS-supplied xattr blob one attribute at a\ntime. For each attribute it reads a 32-bit name length, advances past the\nname bytes, reads a 32-bit value length, records the value pointer, and\nadvances past the value bytes. The two length fields are read with\nceph_decode_32_safe(), but the value bytes themselves are advanced over\nwith a bare \"p += len\" and no ceph_decode_need() check that \"len\" bytes\nremain in the blob.\n\nFor every attribute except the last, the next iteration\u0027s\nceph_decode_32_safe() on the following name length implicitly verifies\nthat the previous value did not run past the blob end. The final\nattribute has no successor, so its decoded value length is never checked\nagainst the blob bounds. A malicious or compromised metadata server can\nset the last attribute\u0027s value length larger than the bytes actually\npresent in the blob.\n\nThe blob is a dedicated kvmalloc() allocation sized to the wire length\n(ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the\noversized length in xattr-\u003eval_len verbatim, and a later getxattr(2) runs\nmemcpy(value, xattr-\u003eval, xattr-\u003eval_len) into a user-supplied buffer,\ncopying bytes past the end of the allocation back to user space.\n\nImpact: a malicious metadata server discloses adjacent kernel heap bytes\nto a local user via getxattr(2) on a CephFS file. Add the missing\nceph_decode_need() so an out-of-bounds value length on the final\nattribute fails the decode and returns -EIO instead of being stored.",
  "id": "GHSA-j8wr-c6w3-j472",
  "modified": "2026-09-13T09:32:26Z",
  "published": "2026-09-11T21:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89649"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1dd356310b1660215f9a3626580bf8b363ef981e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/38be2f3c41ecaba58bb92dc16603e09ba9fd64f1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/68d541754d6cd3bb98d1fd8314f57e5eb533557d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b12b3320c81fd72ab36388fb2445fec9c3038f10"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

MSRC_CVE-2026-89649

Vulnerability from csaf_microsoft - Published: 2026-09-13 01:04 - Updated: 2026-09-13 01:04

Summary

ceph: bound xattr value length in __build_xattrs()

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

CVE-2026-89649

Affected products

Under investigation 1 product

Product	Identifier	Version	Remediation
Unresolved product id: 17084-1		—

References

4 references

URL	Category
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self
https://support.microsoft.com/lifecycle	external
https://www.first.org/cvss	external
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self

JSON

To clipboard

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-89649 ceph: bound xattr value length in __build_xattrs() - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89649.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "ceph: bound xattr value length in __build_xattrs()",
    "tracking": {
      "current_release_date": "2026-09-13T01:04:49.000Z",
      "generator": {
        "date": "2026-09-13T07:02:34.805Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-89649",
      "initial_release_date": "2026-09-13T01:04:49.000Z",
      "revision_history": [
        {
          "date": "2026-09-13T01:04:49.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "category": "product_name",
            "name": "azl3 kernel 0:6.6.150.1-1.azl3",
            "product": {
              "name": "azl3 kernel 0:6.6.150.1-1.azl3",
              "product_id": "1"
            }
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 kernel 0:6.6.150.1-1.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-89649",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "under_investigation": [
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-89649 ceph: bound xattr value length in __build_xattrs() - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89649.json"
        }
      ],
      "title": "ceph: bound xattr value length in __build_xattrs()"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-89649 (GCVE-0-2026-89649)

FKIE_CVE-2026-89649

GHSA-J8WR-C6W3-J472

MSRC_CVE-2026-89649

Tags

Sightings

Nomenclature