SB20260812124 - Out-of-bounds write in Linux kernel drivers/firmware/arm_ffa/driver.c arm_ffa memory region descriptor handling

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-68400)

CWE-ID: CWE-787 - Out-of-bounds write

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 cause a denial of service.

The vulnerability exists due to an out-of-bounds write in the arm_ffa memory region descriptor handling code when calculating endpoint memory access descriptor offsets while processing memory region descriptors. A local user can trigger the vulnerable code path with a crafted descriptor layout to cause a denial of service.

The issue arises from using a default structure size instead of the descriptor's ep_mem_offset value, which can cause calculated descriptor offsets to exceed the fragment size.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/8ef18f0ab3c0ec1eac77289f5a542bd96a8a6d66
• https://git.kernel.org/stable/c/b39b08e6bee812514b449dc874076890e6b871a0
• https://git.kernel.org/stable/c/b4d961351aa84fdf0148783fb1f3a1391b8a0adb