Vulnerability-Lookup

CVE-2026-74723 (GCVE-0-2026-74723)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-08-25 05:42

Title

btrfs: lzo: reject inline extents without valid headers

Summary

In the Linux kernel, the following vulnerability has been resolved: btrfs: lzo: reject inline extents without valid headers [BUG] For a crafted btrfs image, the following KASAN can be triggered when reading an inline lzo compressed file extent: BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700 Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77 Call Trace: <TASK> dump_stack_lvl+0x5b/0x70 print_report+0xd1/0x610 kasan_report+0xe0/0x110 __asan_report_load_n_noabort+0x13/0x20 lzo_decompress+0x57d/0x700 btrfs_decompress+0x140/0x1c0 uncompress_inline+0x147/0x1b0 btrfs_get_extent+0xb23/0x10a0 btrfs_do_readpage.constprop.0+0x538/0x1ac0 btrfs_readahead+0x32f/0x5f0 read_pages+0x16f/0x850 page_cache_ra_unbounded+0x296/0x490 do_page_cache_ra+0xd9/0x130 page_cache_sync_ra+0x3ee/0x6f0 filemap_get_pages+0x306/0x15c0 filemap_read+0x329/0xd00 btrfs_file_read_iter+0x1f8/0x2b0 vfs_read+0x4ef/0x720 ksys_read+0xf8/0x1d0 __x64_sys_read+0x71/0xb0 x64_sys_call+0x1ab0/0x1b70 do_syscall_64+0x61/0x470 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> [CAUSE] For an inline lzo compressed file extent, there should always be one lzo header, recording the total length of the compressed data, followed by one segment header, recording the compressed lzo payload. But if a crafted inline lzo compressed file extent contains only an lzo header, without the segment header or payload, lzo_decompress() will still try to read the segment header, causing a read beyond the item boundary. Furthermore if the inline lzo compressed file extent is the first item of the leaf, it will be at the extent buffer boundary. The above out-of-boundary read will go beyond the extent buffer boundary, triggering the above KASAN report. [FIX] Validate the total length of the inlined lzo compressed file extent, to make sure there is at least one LZO header and one segment header, and a non-zero payload. [ Rework the commit message to remove slop ]

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

2 references

URL	Tags
https://git.kernel.org/stable/c/fc50b475ad27f50b4…
https://git.kernel.org/stable/c/0fa78ef637deb5dbe…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: a6fa6fae40ec336c7df6155255ae64ebef43a8bc , < fc50b475ad27f50b4dcc98fc4c44e8802bc1b248 (git) Affected: a6fa6fae40ec336c7df6155255ae64ebef43a8bc , < 0fa78ef637deb5dbe341582f88553a4bce496de0 (git)	guessed
Linux	Linux	Affected: 2.6.38 Unaffected: 0 , < 2.6.38 (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/lzo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fc50b475ad27f50b4dcc98fc4c44e8802bc1b248",
              "status": "affected",
              "version": "a6fa6fae40ec336c7df6155255ae64ebef43a8bc",
              "versionType": "git"
            },
            {
              "lessThan": "0fa78ef637deb5dbe341582f88553a4bce496de0",
              "status": "affected",
              "version": "a6fa6fae40ec336c7df6155255ae64ebef43a8bc",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/lzo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.38"
            },
            {
              "lessThan": "2.6.38",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: lzo: reject inline extents without valid headers\n\n[BUG]\nFor a crafted btrfs image, the following KASAN can be triggered when\nreading an inline lzo compressed file extent:\n\n  BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700\n  Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77\n\n  Call Trace:\n   \u003cTASK\u003e\n   dump_stack_lvl+0x5b/0x70\n   print_report+0xd1/0x610\n   kasan_report+0xe0/0x110\n   __asan_report_load_n_noabort+0x13/0x20\n   lzo_decompress+0x57d/0x700\n   btrfs_decompress+0x140/0x1c0\n   uncompress_inline+0x147/0x1b0\n   btrfs_get_extent+0xb23/0x10a0\n   btrfs_do_readpage.constprop.0+0x538/0x1ac0\n   btrfs_readahead+0x32f/0x5f0\n   read_pages+0x16f/0x850\n   page_cache_ra_unbounded+0x296/0x490\n   do_page_cache_ra+0xd9/0x130\n   page_cache_sync_ra+0x3ee/0x6f0\n   filemap_get_pages+0x306/0x15c0\n   filemap_read+0x329/0xd00\n   btrfs_file_read_iter+0x1f8/0x2b0\n   vfs_read+0x4ef/0x720\n   ksys_read+0xf8/0x1d0\n   __x64_sys_read+0x71/0xb0\n   x64_sys_call+0x1ab0/0x1b70\n   do_syscall_64+0x61/0x470\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n   \u003c/TASK\u003e\n\n[CAUSE]\nFor an inline lzo compressed file extent, there should always be one lzo\nheader, recording the total length of the compressed data, followed by\none segment header, recording the compressed lzo payload.\n\nBut if a crafted inline lzo compressed file extent contains only an lzo\nheader, without the segment header or payload, lzo_decompress() will\nstill try to read the segment header, causing a read beyond the item\nboundary.\n\nFurthermore if the inline lzo compressed file extent is the first item\nof the leaf, it will be at the extent buffer boundary. The above\nout-of-boundary read will go beyond the extent buffer boundary,\ntriggering the above KASAN report.\n\n[FIX]\nValidate the total length of the inlined lzo compressed file extent, to\nmake sure there is at least one LZO header and one segment header, and a\nnon-zero payload.\n\n[ Rework the commit message to remove slop ]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - On storage servers exporting a btrfs volume via nfsd or ksmbd, remote client read I/O reaches uncompress_inline\u2192lzo_decompress on the server kernel; crafted inline LZO extents in a mounted image are parsed without local syscall access.\nAC:L - A btrfs image with an inline LZO extent containing only the 4-byte total header deterministically drives get_unaligned_le32 past the kmalloc copy in lzo_decompress(); tree-checker skips compressed-inline validation so mount succeeds and a normal read triggers the slab OOB.\nPR:N - Triggering requires only read access to exported btrfs content (nfsd/ksmbd read, loop-mount with CAP_SYS_ADMIN in a user namespace, or udisks-assisted mount); creating the malformed metadata needs offline image crafting, not init-namespace root on the victim.\nUI:N - Exploitation is the attacker\u0027s own read against an already-mounted/exported btrfs volume containing the crafted extent; no separate victim must mount media, click a dialog, or perform other interaction beyond the attacker\u0027s read/open.\nS:U - The slab out-of-bounds read and any resulting kernel memory misuse stay within the host kernel security domain; no VM escape, IOMMU bypass, or sandbox boundary is crossed.\nC:H - get_unaligned_le32 reads up to four bytes past the kmalloc buffer holding the inline extent, leaking adjacent slab contents that can include kernel pointers and enable further kernel memory disclosure.\nI:H - Slab-out-of-bounds access is kernel memory corruption; adjacent kmalloc objects can be groomed and the disclosed pointers chained into arbitrary write or control-flow hijack primitives during repeated reads.\nA:H - KASAN reports slab-out-of-bounds in lzo_decompress on read; the invalid access can fault into adjacent slab objects and oops the kernel, and repeated reads can destabilize or hang the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:42:03.469Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fc50b475ad27f50b4dcc98fc4c44e8802bc1b248"
        },
        {
          "url": "https://git.kernel.org/stable/c/0fa78ef637deb5dbe341582f88553a4bce496de0"
        }
      ],
      "title": "btrfs: lzo: reject inline extents without valid headers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74723",
    "datePublished": "2026-08-22T15:33:15.196Z",
    "dateReserved": "2026-08-15T05:44:03.929Z",
    "dateUpdated": "2026-08-25T05:42:03.469Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74723",
      "date": "2026-08-25",
      "epss": "0.0038",
      "percentile": "0.30736"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-24T14:44:32.000Z",
      "cve": "CVE-2026-74723",
      "id": "msrc_CVE-2026-74723",
      "initial_release_date": "2026-08-24T01:11:06.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "btrfs: lzo: reject inline extents without valid headers",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74723.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74723\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-22T16:16:47.323\",\"lastModified\":\"2026-08-25T06:18:58.147\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbtrfs: lzo: reject inline extents without valid headers\\n\\n[BUG]\\nFor a crafted btrfs image, the following KASAN can be triggered when\\nreading an inline lzo compressed file extent:\\n\\n  BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700\\n  Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77\\n\\n  Call Trace:\\n   \u003cTASK\u003e\\n   dump_stack_lvl+0x5b/0x70\\n   print_report+0xd1/0x610\\n   kasan_report+0xe0/0x110\\n   __asan_report_load_n_noabort+0x13/0x20\\n   lzo_decompress+0x57d/0x700\\n   btrfs_decompress+0x140/0x1c0\\n   uncompress_inline+0x147/0x1b0\\n   btrfs_get_extent+0xb23/0x10a0\\n   btrfs_do_readpage.constprop.0+0x538/0x1ac0\\n   btrfs_readahead+0x32f/0x5f0\\n   read_pages+0x16f/0x850\\n   page_cache_ra_unbounded+0x296/0x490\\n   do_page_cache_ra+0xd9/0x130\\n   page_cache_sync_ra+0x3ee/0x6f0\\n   filemap_get_pages+0x306/0x15c0\\n   filemap_read+0x329/0xd00\\n   btrfs_file_read_iter+0x1f8/0x2b0\\n   vfs_read+0x4ef/0x720\\n   ksys_read+0xf8/0x1d0\\n   __x64_sys_read+0x71/0xb0\\n   x64_sys_call+0x1ab0/0x1b70\\n   do_syscall_64+0x61/0x470\\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\\n   \u003c/TASK\u003e\\n\\n[CAUSE]\\nFor an inline lzo compressed file extent, there should always be one lzo\\nheader, recording the total length of the compressed data, followed by\\none segment header, recording the compressed lzo payload.\\n\\nBut if a crafted inline lzo compressed file extent contains only an lzo\\nheader, without the segment header or payload, lzo_decompress() will\\nstill try to read the segment header, causing a read beyond the item\\nboundary.\\n\\nFurthermore if the inline lzo compressed file extent is the first item\\nof the leaf, it will be at the extent buffer boundary. The above\\nout-of-boundary read will go beyond the extent buffer boundary,\\ntriggering the above KASAN report.\\n\\n[FIX]\\nValidate the total length of the inlined lzo compressed file extent, to\\nmake sure there is at least one LZO header and one segment header, and a\\nnon-zero payload.\\n\\n[ Rework the commit message to remove slop ]\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/btrfs/lzo.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"a6fa6fae40ec336c7df6155255ae64ebef43a8bc\",\"lessThan\":\"fc50b475ad27f50b4dcc98fc4c44e8802bc1b248\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a6fa6fae40ec336c7df6155255ae64ebef43a8bc\",\"lessThan\":\"0fa78ef637deb5dbe341582f88553a4bce496de0\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/btrfs/lzo.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.38\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.38\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"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:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0fa78ef637deb5dbe341582f88553a4bce496de0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fc50b475ad27f50b4dcc98fc4c44e8802bc1b248\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:56:04+00:00",
      "cve": "CVE-2026-74723",
      "id": "CVE-2026-74723",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "118",
      "product_status:known_not_affected": "156",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: btrfs: lzo: reject inline extents without valid headers",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74723.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-08-23T00:03:55Z",
      "cve": "CVE-2026-74723",
      "id": "CVE-2026-74723",
      "initial_release_date": "2026-08-23T00:03:55Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74723",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74723.json",
      "version": "2"
    }
  }
}

FKIE_CVE-2026-74723

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18

Severity

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

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0fa78ef637deb5dbe341582f88553a4bce496de0
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/fc50b475ad27f50b4dcc98fc4c44e8802bc1b248

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/lzo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fc50b475ad27f50b4dcc98fc4c44e8802bc1b248",
              "status": "affected",
              "version": "a6fa6fae40ec336c7df6155255ae64ebef43a8bc",
              "versionType": "git"
            },
            {
              "lessThan": "0fa78ef637deb5dbe341582f88553a4bce496de0",
              "status": "affected",
              "version": "a6fa6fae40ec336c7df6155255ae64ebef43a8bc",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/lzo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.38"
            },
            {
              "lessThan": "2.6.38",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nbtrfs: lzo: reject inline extents without valid headers\n\n[BUG]\nFor a crafted btrfs image, the following KASAN can be triggered when\nreading an inline lzo compressed file extent:\n\n  BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700\n  Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77\n\n  Call Trace:\n   \u003cTASK\u003e\n   dump_stack_lvl+0x5b/0x70\n   print_report+0xd1/0x610\n   kasan_report+0xe0/0x110\n   __asan_report_load_n_noabort+0x13/0x20\n   lzo_decompress+0x57d/0x700\n   btrfs_decompress+0x140/0x1c0\n   uncompress_inline+0x147/0x1b0\n   btrfs_get_extent+0xb23/0x10a0\n   btrfs_do_readpage.constprop.0+0x538/0x1ac0\n   btrfs_readahead+0x32f/0x5f0\n   read_pages+0x16f/0x850\n   page_cache_ra_unbounded+0x296/0x490\n   do_page_cache_ra+0xd9/0x130\n   page_cache_sync_ra+0x3ee/0x6f0\n   filemap_get_pages+0x306/0x15c0\n   filemap_read+0x329/0xd00\n   btrfs_file_read_iter+0x1f8/0x2b0\n   vfs_read+0x4ef/0x720\n   ksys_read+0xf8/0x1d0\n   __x64_sys_read+0x71/0xb0\n   x64_sys_call+0x1ab0/0x1b70\n   do_syscall_64+0x61/0x470\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n   \u003c/TASK\u003e\n\n[CAUSE]\nFor an inline lzo compressed file extent, there should always be one lzo\nheader, recording the total length of the compressed data, followed by\none segment header, recording the compressed lzo payload.\n\nBut if a crafted inline lzo compressed file extent contains only an lzo\nheader, without the segment header or payload, lzo_decompress() will\nstill try to read the segment header, causing a read beyond the item\nboundary.\n\nFurthermore if the inline lzo compressed file extent is the first item\nof the leaf, it will be at the extent buffer boundary. The above\nout-of-boundary read will go beyond the extent buffer boundary,\ntriggering the above KASAN report.\n\n[FIX]\nValidate the total length of the inlined lzo compressed file extent, to\nmake sure there is at least one LZO header and one segment header, and a\nnon-zero payload.\n\n[ Rework the commit message to remove slop ]"
    }
  ],
  "id": "CVE-2026-74723",
  "lastModified": "2026-08-25T06:18:58.147",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:47.323",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0fa78ef637deb5dbe341582f88553a4bce496de0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fc50b475ad27f50b4dcc98fc4c44e8802bc1b248"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-PRR6-M9GQ-386W

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31

Details

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

btrfs: lzo: reject inline extents without valid headers

[BUG] For a crafted btrfs image, the following KASAN can be triggered when reading an inline lzo compressed file extent:

BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700 Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77

Call Trace: dump_stack_lvl+0x5b/0x70 print_report+0xd1/0x610 kasan_report+0xe0/0x110 __asan_report_load_n_noabort+0x13/0x20 lzo_decompress+0x57d/0x700 btrfs_decompress+0x140/0x1c0 uncompress_inline+0x147/0x1b0 btrfs_get_extent+0xb23/0x10a0 btrfs_do_readpage.constprop.0+0x538/0x1ac0 btrfs_readahead+0x32f/0x5f0 read_pages+0x16f/0x850 page_cache_ra_unbounded+0x296/0x490 do_page_cache_ra+0xd9/0x130 page_cache_sync_ra+0x3ee/0x6f0 filemap_get_pages+0x306/0x15c0 filemap_read+0x329/0xd00 btrfs_file_read_iter+0x1f8/0x2b0 vfs_read+0x4ef/0x720 ksys_read+0xf8/0x1d0 __x64_sys_read+0x71/0xb0 x64_sys_call+0x1ab0/0x1b70 do_syscall_64+0x61/0x470 entry_SYSCALL_64_after_hwframe+0x4b/0x53

[CAUSE] For an inline lzo compressed file extent, there should always be one lzo header, recording the total length of the compressed data, followed by one segment header, recording the compressed lzo payload.

But if a crafted inline lzo compressed file extent contains only an lzo header, without the segment header or payload, lzo_decompress() will still try to read the segment header, causing a read beyond the item boundary.

Furthermore if the inline lzo compressed file extent is the first item of the leaf, it will be at the extent buffer boundary. The above out-of-boundary read will go beyond the extent buffer boundary, triggering the above KASAN report.

[FIX] Validate the total length of the inlined lzo compressed file extent, to make sure there is at least one LZO header and one segment header, and a non-zero payload.

[ Rework the commit message to remove slop ]

Severity

9.8 (Critical)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-74723"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:47Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: lzo: reject inline extents without valid headers\n\n[BUG]\nFor a crafted btrfs image, the following KASAN can be triggered when\nreading an inline lzo compressed file extent:\n\n  BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700\n  Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77\n\n  Call Trace:\n   \u003cTASK\u003e\n   dump_stack_lvl+0x5b/0x70\n   print_report+0xd1/0x610\n   kasan_report+0xe0/0x110\n   __asan_report_load_n_noabort+0x13/0x20\n   lzo_decompress+0x57d/0x700\n   btrfs_decompress+0x140/0x1c0\n   uncompress_inline+0x147/0x1b0\n   btrfs_get_extent+0xb23/0x10a0\n   btrfs_do_readpage.constprop.0+0x538/0x1ac0\n   btrfs_readahead+0x32f/0x5f0\n   read_pages+0x16f/0x850\n   page_cache_ra_unbounded+0x296/0x490\n   do_page_cache_ra+0xd9/0x130\n   page_cache_sync_ra+0x3ee/0x6f0\n   filemap_get_pages+0x306/0x15c0\n   filemap_read+0x329/0xd00\n   btrfs_file_read_iter+0x1f8/0x2b0\n   vfs_read+0x4ef/0x720\n   ksys_read+0xf8/0x1d0\n   __x64_sys_read+0x71/0xb0\n   x64_sys_call+0x1ab0/0x1b70\n   do_syscall_64+0x61/0x470\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n   \u003c/TASK\u003e\n\n[CAUSE]\nFor an inline lzo compressed file extent, there should always be one lzo\nheader, recording the total length of the compressed data, followed by\none segment header, recording the compressed lzo payload.\n\nBut if a crafted inline lzo compressed file extent contains only an lzo\nheader, without the segment header or payload, lzo_decompress() will\nstill try to read the segment header, causing a read beyond the item\nboundary.\n\nFurthermore if the inline lzo compressed file extent is the first item\nof the leaf, it will be at the extent buffer boundary. The above\nout-of-boundary read will go beyond the extent buffer boundary,\ntriggering the above KASAN report.\n\n[FIX]\nValidate the total length of the inlined lzo compressed file extent, to\nmake sure there is at least one LZO header and one segment header, and a\nnon-zero payload.\n\n[ Rework the commit message to remove slop ]",
  "id": "GHSA-prr6-m9gq-386w",
  "modified": "2026-08-25T06:31:30Z",
  "published": "2026-08-22T18:30:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74723"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0fa78ef637deb5dbe341582f88553a4bce496de0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fc50b475ad27f50b4dcc98fc4c44e8802bc1b248"
    }
  ],
  "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"
    }
  ]
}

MSRC_CVE-2026-74723

Vulnerability from csaf_microsoft - Published: 2026-08-24 01:11 - Updated: 2026-08-24 14:44

Summary

btrfs: lzo: reject inline extents without valid headers

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-2026-74723

Affected products

Known affected 1 product

Product	Identifier	Version	Remediation
Unresolved product id: 17084-1		—	None Available

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-2026-74723 btrfs: lzo: reject inline extents without valid headers - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74723.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": "btrfs: lzo: reject inline extents without valid headers",
    "tracking": {
      "current_release_date": "2026-08-24T14:44:32.000Z",
      "generator": {
        "date": "2026-08-25T07:02:58.282Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-74723",
      "initial_release_date": "2026-08-24T01:11:06.000Z",
      "revision_history": [
        {
          "date": "2026-08-24T01:11:06.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-08-24T14:44:32.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "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"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "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": "product_name",
            "name": "kernel"
          }
        ],
        "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-2026-74723",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_affected": [
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-74723 btrfs: lzo: reject inline extents without valid headers - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74723.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-08-24T01:11:06.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-1"
          ]
        }
      ],
      "title": "btrfs: lzo: reject inline extents without valid headers"
    }
  ]
}

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-2026-74723 (GCVE-0-2026-74723)

FKIE_CVE-2026-74723

GHSA-PRR6-M9GQ-386W

MSRC_CVE-2026-74723

Tags

Sightings

Nomenclature