Heap-based buffer overflow in Linux kernel - CVE-2026-99109
Published: October 29, 2026
Vulnerability identifier: #VU158480
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-99109
CWE-ID: CWE-122
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service through kernel memory corruption.
The vulnerability exists due to a heap-based buffer overflow in the Linux kernel SMB client's CIFSSMBSetEA() function when processing extended attribute values on an SMB1 mount. A local user can invoke setxattr() with a specially crafted attribute name and value to write beyond the allocated request buffer and potentially crash the kernel.
Affected software
Linux kernel
How to mitigate CVE-2026-99109
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3