PT-2026-61456 · Linux · Linux
CVE-2026-64139
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Published
2026-07-19
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Updated
2026-07-19
None
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In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix SID memory leak in set posix acl entries dacl() on overflow
Commit 299f962c0b02 ("ksmbd: use check add overflow() to prevent u16
DACL size overflow") added check add overflow() guards that break out
of the ACE-building loops in set posix acl entries dacl() when the
accumulated DACL size would wrap past 65535.
However, each iteration allocates a struct smb sid via kmalloc obj()
at the top of the loop and relies on the kfree(sid) call at the end
of the loop body (the 'pass same sid' label in the first loop, and
the explicit kfree at the tail of the second loop) to release it.
The newly introduced 'break' statements bypass those kfree() calls,
leaking the sid buffer every time an overflow is detected.
A malicious or malformed file with enough POSIX ACL entries to trip
the overflow check will leak one or more struct smb sid allocations
on every request that touches the file's DACL, providing a trivial
kernel memory exhaustion vector.
Free sid before breaking out of the loops to plug the leak.
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Related Identifiers
Affected Products
Linux