GHSA-q7pg-xjgf-wr6fHighCVSS 7.8
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix unsound scalar...
🔗 CVE IDs covered (1)
📋 Description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR
maybe_fork_scalars() is called for both BPF_AND and BPF_OR when the
source operand is a constant. When dst has signed range [-1, 0], it
forks the verifier state: the pushed path gets dst = 0, the current
path gets dst = -1.
For BPF_AND this is correct: 0 & K == 0.
For BPF_OR this is wrong: 0 | K == K, not 0.
The pushed path therefore tracks dst as 0 when the runtime value is K,
producing an exploitable verifier/runtime divergence that allows
out-of-bounds map access.
Fix this by passing env->insn_idx (instead of env->insn_idx + 1) to
push_stack(), so the pushed path re-executes the ALU instruction with
dst = 0 and naturally computes the correct result for any opcode.
🔗 References (6)
- https://nvd.nist.gov/vuln/detail/CVE-2026-31413
- https://git.kernel.org/stable/c/342aa1ee995ef5bbf876096dc3a5e51218d76fa4
- https://git.kernel.org/stable/c/58bd87d0e69204dbd739e4387a1edb0c4b1644e7
- https://git.kernel.org/stable/c/c845894ebd6fb43226b3118d6b017942550910c5
- https://git.kernel.org/stable/c/d13281ae7ea8902b21d99d10a2c8caf0bdec0455
- https://github.com/advisories/GHSA-q7pg-xjgf-wr6f