CVE-2026-29649: n/a
NEMU has a vulnerability in its RISC-V Hypervisor CSR handling where certain hypervisor environment configuration bits are incorrectly updated due to a machine-mode write to a related control register. This flaw can cause improper enforcement of virtualization settings, potentially leading to unexpected traps or denial of service during cache-block management instructions in virtualized environments. The vulnerability has a critical CVSS score of 9. 8, indicating high impact on confidentiality, integrity, and availability. No patch or official remediation guidance is currently available.
AI Analysis
Technical Summary
CVE-2026-29649 describes an implementation flaw in NEMU's RISC-V Hypervisor CSR handling. Specifically, bits henvcfg[7:4], related to cache-block instructions (CBIE/CBCFE/CBZE), are incorrectly masked or updated based on menvcfg[7:4]. This means a machine-mode write to menvcfg can implicitly modify the hypervisor's environment configuration, leading to incorrect virtualization enforcement. The flaw may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).
Potential Impact
The vulnerability can lead to incorrect enforcement of virtualization configuration, which may cause unexpected traps or denial of service conditions in virtualized environments using NEMU. The CVSS score of 9.8 reflects critical impact on confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary mitigation has been published. Users should monitor vendor communications for updates and consider restricting untrusted machine-mode writes to menvcfg registers if possible as a precaution.
CVE-2026-29649: n/a
Description
NEMU has a vulnerability in its RISC-V Hypervisor CSR handling where certain hypervisor environment configuration bits are incorrectly updated due to a machine-mode write to a related control register. This flaw can cause improper enforcement of virtualization settings, potentially leading to unexpected traps or denial of service during cache-block management instructions in virtualized environments. The vulnerability has a critical CVSS score of 9. 8, indicating high impact on confidentiality, integrity, and availability. No patch or official remediation guidance is currently available.
CVSS v3.1
Score 9.8critical
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-29649 describes an implementation flaw in NEMU's RISC-V Hypervisor CSR handling. Specifically, bits henvcfg[7:4], related to cache-block instructions (CBIE/CBCFE/CBZE), are incorrectly masked or updated based on menvcfg[7:4]. This means a machine-mode write to menvcfg can implicitly modify the hypervisor's environment configuration, leading to incorrect virtualization enforcement. The flaw may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).
Potential Impact
The vulnerability can lead to incorrect enforcement of virtualization configuration, which may cause unexpected traps or denial of service conditions in virtualized environments using NEMU. The CVSS score of 9.8 reflects critical impact on confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary mitigation has been published. Users should monitor vendor communications for updates and consider restricting untrusted machine-mode writes to menvcfg registers if possible as a precaution.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-03-04T00:00:00.000Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e6860319fe3cd2cd2e53bb
Added to database: 4/20/2026, 8:01:07 PM
Last enriched: 4/28/2026, 6:02:32 AM
Last updated: 6/4/2026, 8:34:45 PM
Views: 68
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