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GHSA-WM9R-84GR-484Q

Vulnerability from github – Published: 2026-07-24 18:31 – Updated: 2026-08-27 15:31

Details

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

netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()

netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn't unlock a folio being read for netfs_perform_write() or netfs_write_begin().

However, given that netfs_unlock_abandoned_read_pages() is called after NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller.

Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies.

Severity

9.8 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64216"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-24T16:16:49Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()\n\nnetfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it\nis wanting to unlock and compares that to rreq-\u003eno_unlock_folio so that it\ndoesn\u0027t unlock a folio being read for netfs_perform_write() or\nnetfs_write_begin().\n\nHowever, given that netfs_unlock_abandoned_read_pages() is called _after_\nNETFS_RREQ_IN_PROGRESS is cleared, the one folio that it\u0027s not allowed to\ndereference is the one specified by -\u003eno_unlock_folio as ownership\nimmediately reverts to the caller.\n\nFix this by storing the folio pointer instead and using that rather than\nthe index.  Also fix netfs_unlock_read_folio() where the same applies.",
  "id": "GHSA-wm9r-84gr-484q",
  "modified": "2026-08-27T15:31:28Z",
  "published": "2026-07-24T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64216"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3866d015f33aeedf81338dd99154703bef33faef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6080fa3ecfbb4448a3b47368629534c09b6ec750"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dbe556972100fabb8e5a1b3d2163831ff07b1e8e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-64216 (GCVE-0-2026-64216)

Vulnerability from cvelistv5 – Published: 2026-07-24 15:23 – Updated: 2026-08-27 12:39

Title

netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()

Summary

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages() netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn't unlock a folio being read for netfs_perform_write() or netfs_write_begin(). However, given that netfs_unlock_abandoned_read_pages() is called _after_ NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller. Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies.

Severity

9.8 (Critical)


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

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/d4ae8dba90b89e7bb…
https://git.kernel.org/stable/c/6080fa3ecfbb4448a…
https://git.kernel.org/stable/c/3866d015f33aeedf8…
https://git.kernel.org/stable/c/dbe556972100fabb8…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e , < d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c (git) Affected: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e , < 6080fa3ecfbb4448a3b47368629534c09b6ec750 (git) Affected: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e , < 3866d015f33aeedf81338dd99154703bef33faef (git) Affected: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e , < dbe556972100fabb8e5a1b3d2163831ff07b1e8e (git)
Linux	Linux	Affected: 6.12 Unaffected: 0 , < 6.12 (semver) Unaffected: 6.12.106 , ≤ 6.12.* (semver) Unaffected: 6.18.34 , ≤ 6.18.* (semver) Unaffected: 7.0.11 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/netfs/buffered_read.c",
            "fs/netfs/read_collect.c",
            "fs/netfs/read_retry.c",
            "include/linux/netfs.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c",
              "status": "affected",
              "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e",
              "versionType": "git"
            },
            {
              "lessThan": "6080fa3ecfbb4448a3b47368629534c09b6ec750",
              "status": "affected",
              "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e",
              "versionType": "git"
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/netfs/buffered_read.c",
            "fs/netfs/read_collect.c",
            "fs/netfs/read_retry.c",
            "include/linux/netfs.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.106",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.106",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()\n\nnetfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it\nis wanting to unlock and compares that to rreq-\u003eno_unlock_folio so that it\ndoesn\u0027t unlock a folio being read for netfs_perform_write() or\nnetfs_write_begin().\n\nHowever, given that netfs_unlock_abandoned_read_pages() is called _after_\nNETFS_RREQ_IN_PROGRESS is cleared, the one folio that it\u0027s not allowed to\ndereference is the one specified by -\u003eno_unlock_folio as ownership\nimmediately reverts to the caller.\n\nFix this by storing the folio pointer instead and using that rather than\nthe index.  Also fix netfs_unlock_read_folio() where the same applies."
        }
      ],
      "metrics": [
        {
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            "baseSeverity": "CRITICAL",
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            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable read-for-write completion is used by network filesystem clients including Ceph, SMB, 9P, and AFS. A malicious filesystem peer can induce failed or malformed reads and control completion timing.\nAC:L - Partial buffered writes and concurrent invalidation can repeatedly trigger the race, with an adjacent bug reproducing approximately 30% of repeated attempts. The attacker can influence completion, reuse, and retry timing.\nPR:N - A malicious filesystem server requires no privileges on the victim client; mount and session credentials belong to the victim.\nUI:N - Once the network filesystem is mounted, ordinary or automated writes can exercise the vulnerable path without further human action.\nS:U - The UAF corrupts resources within the host kernel\u0027s existing security authority and does not inherently cross a VM, IOMMU, or sandbox boundary.\nC:H - The stale folio can be freed and reused, and premature unlocking of a replacement page can expose page-cache or kernel contents.\nI:H - If the folio is reused, folio_unlock() can toggle PG_locked on an unrelated page, enabling concurrent memory corruption and potentially code execution.\nA:H - The condition can trigger a VM_BUG_ON_FOLIO kernel crash; incorrect PG_locked state can also cause permanent page-lock waits and system hangs."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T12:39:42.119Z",
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        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/6080fa3ecfbb4448a3b47368629534c09b6ec750"
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          "url": "https://git.kernel.org/stable/c/3866d015f33aeedf81338dd99154703bef33faef"
        },
        {
          "url": "https://git.kernel.org/stable/c/dbe556972100fabb8e5a1b3d2163831ff07b1e8e"
        }
      ],
      "title": "netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64216",
    "datePublished": "2026-07-24T15:23:04.673Z",
    "dateReserved": "2026-07-19T15:36:31.770Z",
    "dateUpdated": "2026-08-27T12:39:42.119Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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