CVE-2026-43350 Details
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: require a full NFS mode SID before reading mode bits parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the mode bits. That assumes the ACE carries three subauthorities, but compare_sids() only compares min(a, b) subauthorities. A malicious server can return an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still matches sid_unix_NFS_mode and then drives the sub_auth[2] read four bytes past the end of the ACE. Require num_subauth >= 3 before treating the ACE as an NFS mode SID. This keeps the fix local to the special-SID mode path without changing compare_sids() semantics for the rest of cifsacl.
A vulnerability in the Linux kernel's CIFS client can lead to a buffer overflow. This issue arises when the CIFS client incorrectly interprets an Access Control Entry (ACE) Security Identifier (SID) as a valid NFS mode SID. The vulnerability is present in the Linux kernel stable group, specifically in the SMB client component. The problem occurs because the 'parse_dacl()' function assumes that the ACE contains three subauthorities. However, a malicious server can craft an ACE with only two subauthorities that still matches the expected NFS mode SID, causing the client to read beyond the end of the ACE and into adjacent memory.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. Instructions for downloading the patched version are available on the Linux kernel's official website.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 5.4, < 6.6.136 >= 6.7, < 6.12.84 >= 6.13, < 6.18.25 >= 6.19, < 7.0.2 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 19, 2026 | CVE Modified | kernel.org |
| Jun 17, 2026 | CVE Modified | kernel.org |
| Jun 1, 2026 | CVE Modified | kernel.org |
| May 15, 2026 | Initial Analysis | [email protected] |
| May 11, 2026 | CVE Modified | kernel.org |
| May 8, 2026 | New CVE Received | kernel.org |