CVE-2026-93811: ksmbd: Fix acl.sd_buf memory leak and invalid sd_size error handling
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: Fix acl.sdbuf memory leak and invalid sdsize error handling
1. When ndrdecodev4ntacl() fails, the code jumped to freendata which only freed n.data, skipping kfree(acl.sdbuf) and leaking the buffer. Zero-initialize struct xattrntacl acl, reorder error labels to outfree to release acl.sdbuf on all error paths.
2. if (acl.sdsize < sizeof(struct smbntsd)) is true, original code returned success without freeing sdbuf and left stale pntsd. Set rc = -EINVAL before jumping to outfree to return error code and free buffer.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.190-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
What are the effects of an NT ACL decode failure in the vulnerable code path?
A failure in ndr_decode_v4_ntacl() can leave acl.sd_buf allocated because the prior error path frees n.data but skips acl.sd_buf. The fix routes this path through cleanup that releases acl.sd_buf.
How does the corrected code handle a security descriptor that is smaller than struct smb_ntsd?
It returns -EINVAL and frees the associated buffer. Previously, this condition could return success, leave the buffer allocated, and retain a stale value in *pntsd.