CVE-2026-29646

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-04-20. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
29.0%
KEV
Not listed

Published

April 20, 2026

Last Modified

April 21, 2026

Advisory Details (7)

Auto-updated Apr 30, 2026
No patch confirmed yet.
generic

fix(csr): fix set/get sip/sie in V mode by sinceforYy · Pull Request #938 · OpenXiangShan/NEMU · GitHub

https://github.com/OpenXiangShan/NEMU/pull/938/commits/55295c46580456d8d5a9d5736e1fda924b8825ab
generic

fix(csr): fix set/get sip/sie in V mode by sinceforYy · Pull Request #938 · OpenXiangShan/NEMU · GitHub

https://github.com/OpenXiangShan/NEMU/pull/938
generic

Mismatch between sie write behavior and mie update under S-mode · Issue #951 · OpenXiangShan/NEMU · GitHub

https://github.com/OpenXiangShan/NEMU/issues/951
generic

Untitled :: RISC-V Ratified Specifications Library

https://docs.riscv.org/reference/isa/unpriv/zicsr.html
generic

Untitled :: RISC-V Ratified Specifications Library

https://docs.riscv.org/reference/isa/priv/supervisor.html
generic

Untitled :: RISC-V Ratified Specifications Library

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

Untitled :: RISC-V Ratified Specifications Library

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

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 44× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 164 total refreshes for this CVE.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-21 15:24 UTCEPSS rescore
  5. 2026-07-20 17:08 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 02:29 UTCEPSS rescore
  10. 2026-07-18 10:04 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-16 17:03 UTCEPSS rescore
  13. 2026-07-16 17:03 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-15 16:57 UTCEPSS rescore
  16. 2026-07-15 02:00 UTCEPSS rescore
  17. 2026-07-15 02:00 UTCEPSS rescore
  18. 2026-07-13 22:30 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-13 06:13 UTCEPSS rescore
  21. 2026-07-12 05:46 UTCEPSS rescore
  22. 2026-07-11 08:27 UTCEPSS rescore
  23. 2026-07-09 19:10 UTCEPSS rescore
  24. 2026-07-08 15:15 UTCEPSS rescore
  25. 2026-07-07 13:46 UTCEPSS rescore
Show 75 more
  1. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 02:23 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-05 02:30 UTCEPSS rescore
  6. 2026-07-04 06:31 UTCEPSS rescore
  7. 2026-07-01 15:06 UTCEPSS rescore
  8. 2026-06-30 23:22 UTCEPSS rescore
  9. 2026-06-28 14:07 UTCEPSS rescore
  10. 2026-06-28 14:07 UTCEPSS rescore
  11. 2026-06-28 04:56 UTCEPSS rescore
  12. 2026-06-28 04:56 UTCEPSS rescore
  13. 2026-06-27 03:08 UTCEPSS rescore
  14. 2026-06-25 13:49 UTCEPSS rescore
  15. 2026-06-25 13:49 UTCEPSS rescore
  16. 2026-06-24 14:05 UTCEPSS rescore
  17. 2026-06-24 14:05 UTCEPSS rescore
  18. 2026-06-23 21:33 UTCEPSS rescore
  19. 2026-06-23 21:32 UTCEPSS rescore
  20. 2026-06-22 14:25 UTCEPSS rescore
  21. 2026-06-22 14:25 UTCEPSS rescore
  22. 2026-06-21 14:56 UTCEPSS rescore
  23. 2026-06-21 14:56 UTCEPSS rescore
  24. 2026-06-21 01:59 UTCEPSS rescore
  25. 2026-06-21 01:59 UTCEPSS rescore
  26. 2026-06-19 19:25 UTCEPSS rescore
  27. 2026-06-19 19:25 UTCEPSS rescore
  28. 2026-06-18 17:52 UTCEPSS rescore
  29. 2026-06-17 17:53 UTCEPSS rescore
  30. 2026-06-17 17:53 UTCEPSS rescore
  31. 2026-06-16 17:52 UTCEPSS rescore
  32. 2026-06-15 17:48 UTCEPSS rescore
  33. 2026-06-15 03:32 UTCGHSA enrichment
  34. 2026-06-14 23:18 UTCEPSS rescore
  35. 2026-06-14 22:57 UTCGHSA enrichment
  36. 2026-06-14 18:51 UTCGHSA enrichment
  37. 2026-06-13 23:00 UTCEPSS rescore
  38. 2026-06-12 23:12 UTCEPSS rescore
  39. 2026-06-12 23:12 UTCEPSS rescore
  40. 2026-06-12 05:27 UTCGHSA enrichment
  41. 2026-06-12 01:48 UTCGHSA enrichment
  42. 2026-06-11 22:10 UTCGHSA enrichment
  43. 2026-06-11 18:32 UTCGHSA enrichment
  44. 2026-06-11 14:00 UTCEPSS rescore
  45. 2026-06-10 22:51 UTCGHSA enrichment
  46. 2026-06-10 22:18 UTCEPSS rescore
  47. 2026-06-10 22:18 UTCEPSS rescore
  48. 2026-06-10 19:13 UTCGHSA enrichment
  49. 2026-06-10 15:35 UTCGHSA enrichment
  50. 2026-06-10 13:22 UTCEPSS rescore
  51. 2026-06-10 11:57 UTCGHSA enrichment
  52. 2026-06-10 08:19 UTCGHSA enrichment
  53. 2026-06-10 03:50 UTCGHSA enrichment
  54. 2026-06-10 00:11 UTCGHSA enrichment
  55. 2026-06-09 17:08 UTCGHSA enrichment
  56. 2026-06-09 13:30 UTCGHSA enrichment
  57. 2026-06-09 09:52 UTCGHSA enrichment
  58. 2026-06-09 04:41 UTCGHSA enrichment
  59. 2026-06-08 14:17 UTCEPSS rescore
  60. 2026-06-08 14:17 UTCEPSS rescore
  61. 2026-06-08 13:30 UTCGHSA enrichment
  62. 2026-06-08 09:52 UTCGHSA enrichment
  63. 2026-06-08 06:13 UTCGHSA enrichment
  64. 2026-06-08 02:34 UTCGHSA enrichment
  65. 2026-06-07 22:56 UTCGHSA enrichment
  66. 2026-06-07 19:18 UTCGHSA enrichment
  67. 2026-06-07 15:40 UTCGHSA enrichment
  68. 2026-06-07 15:25 UTCEPSS rescore
  69. 2026-06-07 15:25 UTCEPSS rescore
  70. 2026-06-07 15:25 UTCEPSS rescore
  71. 2026-06-07 12:01 UTCGHSA enrichment
  72. 2026-06-07 08:23 UTCGHSA enrichment
  73. 2026-06-07 04:44 UTCGHSA enrichment
  74. 2026-06-06 13:47 UTCEPSS rescore
  75. 2026-06-06 13:47 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-29646?
CVE-2026-29646 is a critical vulnerability published on April 20, 2026. 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…
When was CVE-2026-29646 disclosed?
CVE-2026-29646 was first published in the National Vulnerability Database on April 20, 2026, with the most recent update on April 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-29646 actively exploited?
CVE-2026-29646 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 29.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-29646?
CVE-2026-29646 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-29646?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-29646, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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