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VulnerabilityPublished Updated

CVE-2026-31432: Linux kernel · ksmbd: fix OOB write in QUERY_INFO for compound requests

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · CVSS 8.8 High · fixed in fda9522ed6afaec45cabc198d8492270c394c7bc : patch Linux kernel soon.

Data as of 30 Oct 2026, 12:35 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.18.8
Patch
Available – fixed in fda9522ed6afaec45cabc198d8492270c394c7bc, d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09, 850452af77f55d185f9445e1f7a1db53c5e4aad4 +5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=6.1.71 <6.1.191
  • >=5.15.145 <5.16
Fixed in
  • fda9522ed6afaec45cabc198d8492270c394c7bc
  • d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09
  • 850452af77f55d185f9445e1f7a1db53c5e4aad4
  • 533f84264e28c54a79257ea87d2f94a0fcc9a611
  • 515c2daab46021221bdf406bef19bc90a44ec617
  • 075ea208c648cc2bcd616295b711d3637c61de45
  • 6.1.191
  • 5.16
LinuxLinuxAffected
  • =6.6
Fixed in–

AI-suggested

This vulnerability is fixed in Linux kernel versions 6.1.191, 5.16, and related commits. Users and administrators should upgrade affected Linux kernel versions to these fixed releases or later. No additional mitigation is required once patched.

Description

CVE-2026-31432 is a high-severity vulnerability in the Linux kernel's ksmbd component that could cause an out-of-bounds (OOB) write when processing compound SMB requests involving QUERY_INFO(Security). The flaw arises when the first command in a compound request consumes most of the response buffer, leading ksmbd to write beyond the allocated buffer while constructing a security descriptor. This issue has been fixed in Linux kernel versions 6.1.191, 5.16, and related commits.

References

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