CVE-2026-31413

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR<br /> <br /> maybe_fork_scalars() is called for both BPF_AND and BPF_OR when the<br /> source operand is a constant. When dst has signed range [-1, 0], it<br /> forks the verifier state: the pushed path gets dst = 0, the current<br /> path gets dst = -1.<br /> <br /> For BPF_AND this is correct: 0 &amp; K == 0.<br /> For BPF_OR this is wrong: 0 | K == K, not 0.<br /> <br /> The pushed path therefore tracks dst as 0 when the runtime value is K,<br /> producing an exploitable verifier/runtime divergence that allows<br /> out-of-bounds map access.<br /> <br /> Fix this by passing env-&gt;insn_idx (instead of env-&gt;insn_idx + 1) to<br /> push_stack(), so the pushed path re-executes the ALU instruction with<br /> dst = 0 and naturally computes the correct result for any opcode.