CVE-2026-29649

9.8 criticalEPSS 0.4%

Critical (9.8) in xiangshan nemu. EPSS 0.4% chance of exploitation in the next 30 days.

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).

Severity

CVSS 3.1

9.8 critical

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

EPSS: 0.4% chance of exploitation in the next 30 days; higher than 38% of CVEs (scores of 2026-10-31)
CWE: CWE-693
Published: 2026-04-20
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

xiangshan:nemu

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

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