CVE-2026-29643

HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-04-21. NVD baseline CVSS 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: Elevated riskExposed: 0

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

XiangShan (Open-source high-performance RISC-V processor) commit edb1dfaf7d290ae99724594507dc46c2c2125384 (2024-11-28) contains an improper exceptional-condition handling flaw in its CSR subsystem (NewCSR). On affected versions, certain sequences of CSR operations targeting non-existent/custom CSR addresses may trigger an illegal-instruction exception but fail to reliably transfer control to the configured trap handler (mtvec), causing control-flow disruption and potentially leaving the core in a hung or unrecoverable state. This can be exploited by a local attacker able to execute code on the processor to cause a denial of service and potentially inconsistent architectural state.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
48(Track)
EG Risk 48/100SSVC: 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
Severity71% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
6%
KEV
Not listed

Published

April 20, 2026

Last Modified

April 21, 2026

Advisory Details (4)

Auto-updated Jun 14, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
generic

Unable to Handle Specific Sequences of Illegal Instructions · Issue #3959 · OpenXiangShan/XiangShan · GitHub

https://github.com/OpenXiangShan/XiangShan/issues/3959
github_pr

fix(CSR): fix shadow writing for custom PMA CSRs not in `csrRwMap`

Fix merged in OpenXiangShan/XiangShan PR #3966 on 2024-12-01 — awaiting tagged release

https://github.com/OpenXiangShan/XiangShan/pull/3966
generic

Untitled :: RISC-V Ratified Specifications Library

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

Untitled :: RISC-V Ratified Specifications Library

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 25× 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 199 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-29643?
CVE-2026-29643 is a high vulnerability published on April 20, 2026. XiangShan (Open-source high-performance RISC-V processor) commit edb1dfaf7d290ae99724594507dc46c2c2125384 (2024-11-28) contains an improper exceptional-condition handling flaw in its CSR subsystem (NewCSR). On affected versions, certain sequences of CSR operations targeting non-existent/custom CSR…
When was CVE-2026-29643 disclosed?
CVE-2026-29643 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-2026-29643 actively exploited?
CVE-2026-29643 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 94.0% of all scored CVEs.
What is the CVSS score of CVE-2026-29643?
CVE-2026-29643 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-29643?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-29643, 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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