Improper input validation in Linux kernel - CVE-2026-31706
Published: May 2, 2026
Vulnerability identifier: #VU128991
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-31706
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper input validation in smb_inherit_dacl() when processing a tampered parent directory DACL xattr during SMB2 CREATE. A remote user can trigger inheritance of a crafted security.NTACL value to cause a denial of service.
Exploitation requires a parent directory security.NTACL xattr to be tampered while preserving the hash bytes so the xattr check passes.
How to mitigate CVE-2026-31706
Install security update from vendor's repository.