VulnerabilityAnalyzed

CVE-2026-29649

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).

CRITICAL 9.8EPSS 0.45%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.45%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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: 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.45% probability · 38th percentile
CISA KEV: Not listed
Weakness: CWE-693
Affected: xiangshan/nemu
Source: cve@mitre.org

References

https://docs.riscv.org/reference/isa/priv/hypervisor.htmlProduct
https://docs.riscv.org/reference/isa/priv/machine.htmlProduct
https://github.com/OpenXiangShan/NEMU/issues/681Issue Tracking
https://github.com/OpenXiangShan/NEMU/pull/689Issue Tracking, Patch

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.