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VulnerabilityPublished Updated

CVE-2026-43365: Linux kernel · xfs: fix undersized l_iclog_roundoff values

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.2 High · fixed in e88ce9f0536f3b2149afb70625cfc4bd74a4ac6d : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:07 UTC

CVSS 3.1 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in e88ce9f0536f3b2149afb70625cfc4bd74a4ac6d, 446a1f5bb64ba38adb93cb043ff0f7b85e8937ca, 52a8a1ba883defbfe3200baa22cf4cd21985d51a +4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 May 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
  • ≥ a6a65fef5ef8d0a6a0ce514eb66b2f3dfa777b48, < e88ce9f0536f3b2149afb70625cfc4bd74a4ac6d
Fixed in
  • e88ce9f0536f3b2149afb70625cfc4bd74a4ac6d
LinuxLinuxAffected
  • ≥ a6a65fef5ef8d0a6a0ce514eb66b2f3dfa777b48, < 446a1f5bb64ba38adb93cb043ff0f7b85e8937ca
Fixed in
  • 446a1f5bb64ba38adb93cb043ff0f7b85e8937ca
LinuxLinuxAffected
  • ≥ a6a65fef5ef8d0a6a0ce514eb66b2f3dfa777b48, < 52a8a1ba883defbfe3200baa22cf4cd21985d51a
Fixed in
  • 52a8a1ba883defbfe3200baa22cf4cd21985d51a
LinuxLinuxAffected
  • ≥ a6a65fef5ef8d0a6a0ce514eb66b2f3dfa777b48, < 41e91dff2d3974730b5ee50daa8e27ec254cbf91
Fixed in
  • 41e91dff2d3974730b5ee50daa8e27ec254cbf91
LinuxLinuxAffected
  • ≥ a6a65fef5ef8d0a6a0ce514eb66b2f3dfa777b48, < 5e7148402dfc4a5b7894d8e97b15e5c2e70924aa
Fixed in
  • 5e7148402dfc4a5b7894d8e97b15e5c2e70924aa
LinuxLinuxAffected
  • ≥ a6a65fef5ef8d0a6a0ce514eb66b2f3dfa777b48, < 5afae524f83d6a18517298491a5624cb0eae5029
Fixed in
  • 5afae524f83d6a18517298491a5624cb0eae5029

Description

In the Linux kernel, the following vulnerability has been resolved: xfs: fix undersized l_iclog_roundoff values If the superblock doesn't list a log stripe unit, we set the incore log roundoff value to 512. This leads to corrupt logs and unmountable filesystems in generic/617 on a disk with 4k physical sectors... XFS (sda1): Mounting V5 Filesystem ff3121ca-26e6-4b77-b742-aaff9a449e1c XFS (sda1): Torn write (CRC failure) detected at log block 0x318e. Truncating head block from 0x3197. XFS (sda1): failed to locate log tail XFS (sda1): log mount/recovery failed: error -74 XFS (sda1): log mount failed XFS (sda1): Mounting V5 Filesystem ff3121ca-26e6-4b77-b742-aaff9a449e1c XFS (sda1): Ending clean mount ...on the current xfsprogs for-next which has a broken mkfs. xfs_info shows this... meta-data=/dev/sda1 isize=512 agcount=4, agsize=644992 blks = sectsz=4096 attr=2, projid32bit=1 = crc=1 finobt=1, sparse=1, rmapbt=1 = reflink=1 bigtime=1 inobtcount=1 nrext64=1 = exchange=1 metadir=1 data = bsize=4096 blocks=2579968, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0, ftype=1, parent=1 log =internal log bsize=4096 blocks=16384, version=2 = sectsz=4096 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 = rgcount=0 rgsize=268435456 extents = zoned=0 start=0 reserved=0 ...observe that the log section has sectsz=4096 sunit=0, which means that the roundoff factor is 512, not 4096 as you'd expect. We should fix mkfs not to generate broken filesystems, but anyone can fuzz the ondisk superblock so we should be more cautious. I think the inadequate logic predates commit a6a65fef5ef8d0, but that's clearly going to require a different backport.

References

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