High 8.2Published Jul 25, 2026

CVE-2026-64380smb: client: harden POSIX SID length parsing

Updated under an hour ago (Oct 28, 2026, 9:00 PM ET)

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Exploited in the last 30 days

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.

CVSS: 8.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Weakness (CWE): CWE-125
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 349e13ad30b45998bb9937cfe0b32be6f951976d before 171605aed68380c2fa75dff9b3a1ed427c50065b; from 349e13ad30b45998bb9937cfe0b32be6f951976d before 4213c1208978483021d7d125c131de3985d38f61; 349e13ad30b45998bb9937cfe0b32be6f951976d builds before 96e889bc1e759c83f25093e8c2f3da31b4973f30; 349e13ad30b45998bb9937cfe0b32be6f951976d builds before 0de5b8e76847f5de26f364a82c6602c4881c30da; from 349e13ad30b45998bb9937cfe0b32be6f951976d before 427eb7eb46425fec845a43e861f3d6e2899cae59; 349e13ad30b45998bb9937cfe0b32be6f951976d builds before 86c5d470f5d42e61123b2f4b4f0b91f4eee5b980; 349e13ad30b45998bb9937cfe0b32be6f951976d builds before 46a84715a015cb48e1b9c219dc88c03d8a541ea4; 349e13ad30b45998bb9937cfe0b32be6f951976d builds before 7ad2bcf2441430bb2e918fb3ef9a90d775a6e422	CNA record
linux linux_kernel linux:linux_kernel	from 5.7 before 5.10.261; from 5.11 before 5.15.212; from 5.16 before 6.1.178; from 6.2 before 6.6.145; from 6.7 before 6.12.96; from 6.13 before 6.18.39; from 6.19 before 7.1.4; 7.2	NVD

References

References

https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b	patch
https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61	patch
https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30	patch
https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da	patch
https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59	patch
https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980	patch
https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4	patch
https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.