CVE-2026-31478

critical

Published 2026-04-22 · Modified 2026-04-27

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CVSS v3

9.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v4 NEW

—

not yet in upstream

VIR risk

9.8

Description

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.

Predictions

Exploit likelihood

97%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

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OS impact

Linux kernel Affected 3 releases

Version	Status	Fixed in
7.0	Affected	—
6.6	Affected	—
—	Affected	`5.15.203`

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

Debian Fixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`6.12.85-1`
sid	Fixed	`6.19.11-1`
forky	Fixed	`6.19.11-1`
bullseye	Fixed	`0`
bookworm	Fixed	`6.1.170-1`

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.