---
id: "CVE-2026-98572"
kind: "vulnerability"
aliases: ["CVE-2026-98572"]
title: "Linux kernel: BPF jump comparisons on MIPS32 return wrong results"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["bpf", "infrastructure", "linux-kernel", "mips32"]
not_affected_if: ["non-mips32-hardware"]
published_at: "2026-10-18T16:17:09+00:00"
first_seen_at: "2026-10-23T21:57:15+00:00"
updated_at: "2026-10-25T05:23:11+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98572", "first_seen_at": "2026-10-23T21:57:15+00:00"}]
---

# Linux kernel: BPF jump comparisons on MIPS32 return wrong results

The Linux kernel's BPF JIT for MIPS32 emitted an addu instruction instead of addiu for immediate JEQ/JNE jumps, so a negative immediate value was compared incorrectly. The sources do not say that an attacker can use this to run code or read data.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-10-23T21:57:15+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98572

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix immediate JMP JEQ/JNE on MIPS32

An addu instruction was emitted instead of addiu, causing the immediate
value 1 to be interpreted as register $at. This made the comparison
result invalid when the immediate operand was negative. Note that $at
is mapped to BPF_REG_AX, which is used for constant blinding.

Fix the instruction to use the immediate form.

Found with test_bpf on MIPS32r1 emulated by QEMU.

---

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