Bug 2507145 (CVE-2026-64380) - CVE-2026-64380 kernel: smb: client: harden POSIX SID length parsing
Summary: CVE-2026-64380 kernel: smb: client: harden POSIX SID length parsing
Keywords:
Status: NEW
Alias: CVE-2026-64380
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-25 10:07 UTC by OSIDB Bzimport
Modified: 2026-07-29 16:20 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-07-25 10:07:24 UTC 
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.
Comment 1 TEJ RATHI 2026-07-29 16:14:12 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072525-CVE-2026-64380-95d8@gregkh/T
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