PT-2026-32152 · Linux · Linux

Published 2026-04-12 · Updated 2026-04-12 · CVE-2026-31413

Mitre

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.

Related Identifiers

CVE-2026-31413

Affected Products

Linux

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-31413 · Security Note
• https://git.kernel.org/stable/c/d13281ae7ea8902b21d99d10a2c8caf0bdec0455 · Note
• https://git.kernel.org/stable/c/58bd87d0e69204dbd739e4387a1edb0c4b1644e7 · Note
• https://git.kernel.org/stable/c/c845894ebd6fb43226b3118d6b017942550910c5 · Note
• https://git.kernel.org/stable/c/342aa1ee995ef5bbf876096dc3a5e51218d76fa4 · Note