CVE-2026-29649

CVSS 9.8 CRITICALEPSS 0.4%CWE-693

Vexday Risk Score

28Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 9.8EPSS 0.4%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

20 Apr 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

NEMU contains an implementation flaw in its RISC-V Hypervisor CSR handling where henvcfg[7:4] (CBIE/CBCFE/CBZE-related fields) is incorrectly masked/updated based on menvcfg[7:4], so a machine-mode write to menvcfg can implicitly modify the hypervisor's environment configuration. This can lead to incorrect enforcement of virtualization configuration and may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).

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

Affected products

n/a · n/a

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References

https://docs.riscv.org/reference/isa/priv/hypervisor.html https://docs.riscv.org/reference/isa/priv/machine.html https://github.com/OpenXiangShan/NEMU/issues/681 https://github.com/OpenXiangShan/NEMU/pull/689