In OpenXiangShan NEMU prior to 55295c4, when running with RVH (Hypervisor extension)…
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
In OpenXiangShan NEMU prior to 55295c4, when running with RVH (Hypervisor extension) enabled, a VS-mode guest write to the supervisor interrupt-enable CSR (sie) may be handled incorrectly and can influence machine-level interrupt enable state (mie). This breaks privilege/virtualization isolation and can lead to denial of service or privilege-boundary violation in environments relying on NEMU for correct interrupt virtualization.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-29646
- 2026-10-03 Alias added: GHSA-729m-5x6m-wwxv
- 2026-10-25 EPSS moved to the below the 50th percentile
References
Other 7
- https://docs.riscv.org/reference/isa/priv/machine.html
- https://github.com/OpenXiangShan/NEMU/issues/951
- https://github.com/OpenXiangShan/NEMU/pull/938
- https://github.com/OpenXiangShan/NEMU/pull/938/commits/55295c46580456d8d5a9d5736e1fda924b8825ab
- https://docs.riscv.org/reference/isa/unpriv/zicsr.html
- https://docs.riscv.org/reference/isa/priv/supervisor.html
- https://docs.riscv.org/reference/isa/priv/hypervisor.html
Sources
- CVE-2026-29646 · CVE Program
- CVE-2026-29646 · NVD
- FIRST EPSS
- GHSA-729m-5x6m-wwxv · GitHub Advisory Database · CC BY 4.0
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