Skip to main content
VulnerabilityPublished Updated

CVE-2026-31666: Linux kernel · Unchecked Error Condition

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in ab1e022379c3c811aa72da8eb0c7507859a1d0f5 : patch Linux kernel soon.

Data as of 26 Oct 2026, 10:24 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 1% 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 cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in ab1e022379c3c811aa72da8eb0c7507859a1d0f5, 4125a194db4a6cf91f619f38788272651cb97dce, 450e6a685d0cad95b15f8af152057bd0bf79f50b +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Apr 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 Linux kernel to ab1e022379c3c811aa72da8eb0c7507859a1d0f5, 4125a194db4a6cf91f619f38788272651cb97dce, 450e6a685d0cad95b15f8af152057bd0bf79f50b or 316fb1b3169efb081d2db910cbbfef445afa03b9.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 1618aa3c2e0163f5ac34d514ae89474521910536, < ab1e022379c3c811aa72da8eb0c7507859a1d0f5
Fixed in
  • ab1e022379c3c811aa72da8eb0c7507859a1d0f5
LinuxLinuxAffected
  • ≥ 1618aa3c2e0163f5ac34d514ae89474521910536, < 4125a194db4a6cf91f619f38788272651cb97dce
Fixed in
  • 4125a194db4a6cf91f619f38788272651cb97dce
LinuxLinuxAffected
  • ≥ 1618aa3c2e0163f5ac34d514ae89474521910536, < 450e6a685d0cad95b15f8af152057bd0bf79f50b
Fixed in
  • 450e6a685d0cad95b15f8af152057bd0bf79f50b
LinuxLinuxAffected
  • ≥ 1618aa3c2e0163f5ac34d514ae89474521910536, < 316fb1b3169efb081d2db910cbbfef445afa03b9
Fixed in
  • 316fb1b3169efb081d2db910cbbfef445afa03b9
LinuxLinuxAffected
  • =6.10
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() After commit 1618aa3c2e01 ("btrfs: simplify return variables in lookup_extent_data_ref()"), the err and ret variables were merged into a single ret variable. However, when btrfs_next_leaf() returns 0 (success), ret is overwritten from -ENOENT to 0. If the first key in the next leaf does not match (different objectid or type), the function returns 0 instead of -ENOENT, making the caller believe the lookup succeeded when it did not. This can lead to operations on the wrong extent tree item, potentially causing extent tree corruption. Fix this by returning -ENOENT directly when the key does not match, instead of relying on the ret variable.

References

Community reviews

Loading reviews…