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VulnerabilityPublished Updated

CVE-2026-31707: Linux kernel · ksmbd: validate response sizes in ipc_validate_msg()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · CVSS 7.1 High · fixed in d6a6aa81eac2c9bff66dc6e191179cb69a14426b : patch Linux kernel soon.

Data as of 30 Oct 2026, 12:49 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.17.1
Patch
Available – fixed in d6a6aa81eac2c9bff66dc6e191179cb69a14426b, bf396208418371174869baba9434535cd3288e80, 52518503a1a00bc33e9522c4eb05df023e3ae978 +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 May 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
  • ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < d6a6aa81eac2c9bff66dc6e191179cb69a14426b
Fixed in
  • d6a6aa81eac2c9bff66dc6e191179cb69a14426b
LinuxLinuxAffected
  • ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < bf396208418371174869baba9434535cd3288e80
Fixed in
  • bf396208418371174869baba9434535cd3288e80
LinuxLinuxAffected
  • ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 52518503a1a00bc33e9522c4eb05df023e3ae978
Fixed in
  • 52518503a1a00bc33e9522c4eb05df023e3ae978
LinuxLinuxAffected
  • ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 299db777ea0cfa5c407e41b045c24a14c034c27b
Fixed in
  • 299db777ea0cfa5c407e41b045c24a14c034c27b
LinuxLinuxAffected
  • ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 99c631d0366c1eab8fb188fe66425f4581ebdde4
Fixed in
  • 99c631d0366c1eab8fb188fe66425f4581ebdde4
LinuxLinuxAffected
  • ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 7dd0c858e1909769a4c91842724315ee74f1a5f1
Fixed in
  • 7dd0c858e1909769a4c91842724315ee74f1a5f1

AI-suggested

A patch is available and has been applied in fixed Linux kernel commits referenced by their hashes. Users should update to a fixed kernel version that includes these commits. Since this is a kernel vulnerability, updating the kernel to a patched version is the recommended mitigation. The vendor manages remediation for this cloud-hosted service if applicable. No additional mitigations are specified.

Description

CVE-2026-31707 is a high-severity vulnerability in the Linux kernel's ksmbd component affecting version 5.15. It involves integer overflow in the ipc_validate_msg() function when calculating expected message sizes for certain response types, allowing unverified length values to be trusted downstream. The flaw arises from arithmetic on attacker-controlled fields that can wrap around, bypassing size checks and potentially leading to memory corruption. The issue has been fixed by adding overflow checks and bounds validation to prevent these overflows.

References

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