SB20261029161 - Heap-based buffer overflow in Linux kernel BSG reply buffer allocation in block/bsg-lib.c and ufshcd_advanced_rpmb_req_handler() in the UFS BSG command handling path

Description

This security bulletin contains information about 1 vulnerability.

1) Heap-based buffer overflow (CVE-ID: CVE-2026-99157)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 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]

The vulnerability allows a local user to corrupt kernel heap memory, potentially causing a denial of service.

The vulnerability exists due to a heap-based buffer overflow in the Linux kernel BSG reply handling when processing UFS Advanced RPMB commands that return an EHS. A local user can trigger processing of such a command to cause ufshcd_advanced_rpmb_req_handler() to write a 104-byte reply, consisting of a 40-byte header and a 64-byte EHS, into a 96-byte heap buffer, corrupting eight bytes beyond its boundary and potentially causing a denial of service.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/2effbe746452c108188f85a6951f2b0b65653840
• https://git.kernel.org/stable/c/7a755f6d47b811d3abd93c1642ce5e63894540b8
• https://git.kernel.org/stable/c/ec6b083915e8146e147314a5f4f1285d07b57bfc