SB2026050609 - Always-Incorrect Control Flow Implementation in Linux kernel bpf

Description

This security bulletin contains information about 1 vulnerability.

1) Always-Incorrect Control Flow Implementation (CVE-ID: CVE-2026-43070)

CWE-ID: CWE-670 - Always-Incorrect Control Flow Implementation

CVSSv4: 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/E:U/U:Clear

The vulnerability allows a local user to cause out-of-bounds memory accesses.

The vulnerability exists due to improper state management in the BPF verifier when processing a BPF_END byte-swap operation. A local user can load a crafted BPF program to cause out-of-bounds memory accesses.

The issue occurs because a register ID is not reset after an in-place byte-swap, allowing verifier bounds learned from the swapped register to be incorrectly propagated to a linked register.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0d15c3611a2cc5d08993545d4032055ae10ae2c1
• https://git.kernel.org/stable/c/a17443af874229408ce6b78e2c8a2b5adeb4b7d8
• https://git.kernel.org/stable/c/a3125bc01884431d30d731461634c8295b6f0529