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CVE-2026-31413 Detail

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.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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URL Source(s) Tag(s)
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-125 Out-of-bounds Read cwe source acceptance level NIST  

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-31413
NVD Published Date:
04/12/2026
NVD Last Modified:
05/20/2026
Source:
kernel.org