CVE-2026-64380

smb: client: harden POSIX SID length parsing

State: Published
Severity: 8.2 High
Published: Jul 25, 2026
Updated: Oct 19, 2026
Reserved: Jul 19, 2026

Description

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

smb: client: harden POSIX SID length parsing

posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.

Scores

CVSS	Score	Vector	Source
3.1	8.2 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H	Linux

Weaknesses

CWE-125 Out-of-bounds Read

Affected Products

Product	Versions
LinuxLinux	349e13ad30b45998bb9937cfe0b32be6f951976d to before 171605aed68380c2fa75dff9b3a1ed427c50065bAffected 349e13ad30b45998bb9937cfe0b32be6f951976d to before 4213c1208978483021d7d125c131de3985d38f61Affected 349e13ad30b45998bb9937cfe0b32be6f951976d to before 96e889bc1e759c83f25093e8c2f3da31b4973f30Affected 349e13ad30b45998bb9937cfe0b32be6f951976d to before 0de5b8e76847f5de26f364a82c6602c4881c30daAffected 349e13ad30b45998bb9937cfe0b32be6f951976d to before 427eb7eb46425fec845a43e861f3d6e2899cae59Affected 349e13ad30b45998bb9937cfe0b32be6f951976d to before 86c5d470f5d42e61123b2f4b4f0b91f4eee5b980Affected 349e13ad30b45998bb9937cfe0b32be6f951976d to before 46a84715a015cb48e1b9c219dc88c03d8a541ea4Affected 349e13ad30b45998bb9937cfe0b32be6f951976d to before 7ad2bcf2441430bb2e918fb3ef9a90d775a6e422Affected
LinuxLinux	5.7Affected before 5.7Not affected 5.10.261 through 5.10.Not affected 5.15.212 through 5.15.Not affected 6.1.178 through 6.1.Not affected 6.6.145 through 6.6.Not affected 6.12.96 through 6.12.Not affected 6.18.39 through 6.18.Not affected 7.1.4 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

349e13ad30b45998bb9937cfe0b32be6f951976d to before 171605aed68380c2fa75dff9b3a1ed427c50065bAffected
349e13ad30b45998bb9937cfe0b32be6f951976d to before 4213c1208978483021d7d125c131de3985d38f61Affected
349e13ad30b45998bb9937cfe0b32be6f951976d to before 96e889bc1e759c83f25093e8c2f3da31b4973f30Affected
349e13ad30b45998bb9937cfe0b32be6f951976d to before 0de5b8e76847f5de26f364a82c6602c4881c30daAffected
349e13ad30b45998bb9937cfe0b32be6f951976d to before 427eb7eb46425fec845a43e861f3d6e2899cae59Affected
349e13ad30b45998bb9937cfe0b32be6f951976d to before 86c5d470f5d42e61123b2f4b4f0b91f4eee5b980Affected
349e13ad30b45998bb9937cfe0b32be6f951976d to before 46a84715a015cb48e1b9c219dc88c03d8a541ea4Affected
349e13ad30b45998bb9937cfe0b32be6f951976d to before 7ad2bcf2441430bb2e918fb3ef9a90d775a6e422Affected

LinuxLinux

5.7Affected
before 5.7Not affected
5.10.261 through 5.10.*Not affected
5.15.212 through 5.15.*Not affected
6.1.178 through 6.1.*Not affected
6.6.145 through 6.6.*Not affected
6.12.96 through 6.12.*Not affected
6.18.39 through 6.18.*Not affected
7.1.4 through 7.1.*Not affected
7.2 and laterNot affected

References

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