CVE-2026-29649: Xiangshan Nemu

Critical severity, CVSS 9.8. EPSS: 0.7% 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).

Affected products

• Xiangshan Nemu: affected versions not specified

Published 2026-04-20. Last modified 2026-06-17.