CVE-2026-29649

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.

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).

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
59(Track)
EG Risk 59/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
36.6%
KEV
Not listed

Published

April 20, 2026

Last Modified

April 24, 2026

Advisory Details (4)

Auto-updated May 10, 2026
No patch confirmed yet.
generic

fix(henvcfg): fix read value for CSR henvcfg. by NewPaulWalker · Pull Request #689 · OpenXiangShan/NEMU · GitHub

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

Mismatch in Dependency Between `henvcfg` and `menvcfg` in NEMU and XiangShan · Issue #681 · OpenXiangShan/NEMU · GitHub

https://github.com/OpenXiangShan/NEMU/issues/681
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 15× 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 165 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-29649?
CVE-2026-29649 is a critical vulnerability published on April 20, 2026. 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…
When was CVE-2026-29649 disclosed?
CVE-2026-29649 was first published in the National Vulnerability Database on April 20, 2026, with the most recent update on April 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-29649 actively exploited?
CVE-2026-29649 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 36.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-29649?
CVE-2026-29649 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-29649?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-29649, 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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