CVE-2026-29649

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).

References

https://github.com/OpenXiangShan/NEMU/pull/689

https://github.com/OpenXiangShan/NEMU/issues/681

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

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

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3