CVE-2026-43350
Linux Kernel SID Parsing Buffer Overflow
Publication date: 2026-05-08
Last updated on: 2026-05-08
Assigner: kernel.org
Description
Description
CVSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the Linux kernel's SMB client code related to handling NFS mode SIDs (Security Identifiers). The function parse_dacl() expects an Access Control Entry (ACE) to have three subauthorities when interpreting it as an NFS mode SID. However, compare_sids() only compares the minimum number of subauthorities between two SIDs, allowing a malicious server to craft an ACE with only two subauthorities that still matches the expected SID pattern. This causes parse_dacl() to read beyond the intended memory boundary (reading sub_auth[2] which does not exist), potentially leading to memory corruption or information disclosure. The fix requires that the ACE must have at least three subauthorities before it is treated as an NFS mode SID, preventing the out-of-bounds read.
How can this vulnerability impact me? :
This vulnerability can allow a malicious SMB server to cause the Linux kernel SMB client to read memory beyond the intended bounds. This out-of-bounds read could lead to memory corruption or information disclosure, potentially compromising system stability or leaking sensitive information. An attacker controlling the SMB server could exploit this to disrupt normal operations or gain unauthorized access to data.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability has been resolved in the Linux kernel by requiring that the number of subauthorities (num_subauth) be at least 3 before treating an ACE as an NFS mode SID. To mitigate this vulnerability, you should update your Linux kernel to a version that includes this fix.