CVE-2026-29646

CRITICAL

OpenXiangShan NEMU <55295c4 - Privilege Escalation

Title source: llm

Description

In OpenXiangShan NEMU prior to 55295c4, when running with RVH (Hypervisor extension) enabled, a VS-mode guest write to the supervisor interrupt-enable CSR (sie) may be handled incorrectly and can influence machine-level interrupt enable state (mie). This breaks privilege/virtualization isolation and can lead to denial of service or privilege-boundary violation in environments relying on NEMU for correct interrupt virtualization.

References (7)

https://docs.riscv.org/reference/isa/priv/machine.html

https://github.com/OpenXiangShan/NEMU/issues/951

https://github.com/OpenXiangShan/NEMU/pull/938

https://github.com/OpenXiangShan/NEMU/pull/938/commits/55295c46580456d8d5a9d5736e1fda924b8825ab

https://docs.riscv.org/reference/isa/unpriv/zicsr.html

https://docs.riscv.org/reference/isa/priv/supervisor.html

https://docs.riscv.org/reference/isa/priv/hypervisor.html

Scores

CVSS v3 9.8

EPSS 0.0008

EPSS Percentile 23.5%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact total

Details

CWE

CWE-267

Status published

Published Apr 20, 2026

Tracked Since Apr 21, 2026