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VulnerabilityPublished Updated

CVE-2026-74723: Linux kernel · btrfs: lzo: reject inline extents without valid headers

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in fd150d7c8e0ad9d721c011cfd4cc0f3c65bd6834 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in fd150d7c8e0ad9d721c011cfd4cc0f3c65bd6834, fc50b475ad27f50b4dcc98fc4c44e8802bc1b248, 056876c9db1e969bfcf7d8583c7696cc0dd080df +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ a6fa6fae40ec336c7df6155255ae64ebef43a8bc, < fd150d7c8e0ad9d721c011cfd4cc0f3c65bd6834
Fixed in
  • fd150d7c8e0ad9d721c011cfd4cc0f3c65bd6834
LinuxLinuxAffected
  • ≥ a6fa6fae40ec336c7df6155255ae64ebef43a8bc, < fc50b475ad27f50b4dcc98fc4c44e8802bc1b248
Fixed in
  • fc50b475ad27f50b4dcc98fc4c44e8802bc1b248
LinuxLinuxAffected
  • ≥ a6fa6fae40ec336c7df6155255ae64ebef43a8bc, < 056876c9db1e969bfcf7d8583c7696cc0dd080df
Fixed in
  • 056876c9db1e969bfcf7d8583c7696cc0dd080df
LinuxLinuxAffected
  • ≥ a6fa6fae40ec336c7df6155255ae64ebef43a8bc, < 5d00c9c1c951ae82d498eabbdfff973252a05c50
Fixed in
  • 5d00c9c1c951ae82d498eabbdfff973252a05c50
LinuxLinuxAffected
  • ≥ a6fa6fae40ec336c7df6155255ae64ebef43a8bc, < 0fa78ef637deb5dbe341582f88553a4bce496de0
Fixed in
  • 0fa78ef637deb5dbe341582f88553a4bce496de0
LinuxLinuxAffected
  • =2.6.38
Fixed in–

Description

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 ]

References

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