CVE-2026-64380

High

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.

SeverityHigh
CVSS8.2
Exploit probability—
ProductLinux Kernel
PublishedJul 25, 2026
First seenJul 25, 2026

How to fix

Update
  • linux linux_kernel5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4 or later

Affected products

ProductAffected versionsFixed in
linux linux_kernel5.7 ≤ v < 5.10.261, 5.11 ≤ v < 5.15.212, 5.16 ≤ v < 6.1.178, 6.2 ≤ v < 6.6.145, 6.7 ≤ v < 6.12.96, 6.13 ≤ v < 6.18.39, 6.19 ≤ v < 7.1.4, 7.25.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4

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