🛡️ CVE-2026-31478 — kernel

🔴 CVSS 9.8 — Critical ✅ No Known Exploit NVD
9.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()

After this commit (e2b76ab8b5c9 "ksmbd: add support for read compound"),

response buffer management was changed to use dynamic iov array.

In the new design, smb2_calc_max_out_buf_len() expects the second

argument (hdr2_len) to be the offset of ->Buffer field in the

response structure, not a hardcoded magic number.

Fix the remaining call sites to use the correct offsetof() value.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

CVE-2026-31478 is recorded against 2 packages.

  • kernel (from 6.13.0 up to 6.19.11)
  • linux-kernel

Timeline and source

Published on 22 April 2026 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2026-31478 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Critical
CVSS Score 9.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2026-04-22
Updated 2026-08-12
Modified 2026-08-06

Affected Packages

Software From version Fixed in
kernel 6.13.0 6.19.11
linux-kernel — —

Similar Threats

Exploit Protection

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