CVE-2026-29649

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

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, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week

Also known asEUVD-2026-23944 (ENISA EUVD) · GHSA-p786-pp8p-8p3m (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan mitigationThe upstream fix is not in a release yet: until the release ships, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high, then apply it (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 9.8Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

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
9.8CRITICALmedium confidence
EG Risk
59
EG Risk 59/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: An upstream fix is merged but not yet in a tagged release. Until the release ships, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high, then apply it.
EPSS PROB
0.4%
EPSS %ILE
38th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

An upstream fix is merged but not yet in a tagged release. Until the release ships, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high, then apply it.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

April 20, 2026

Last Modified

April 24, 2026

Advisory Details (4)

Auto-updated Oct 8, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
GitHub pull request

fix(henvcfg): fix read value for CSR henvcfg.

Fix merged in OpenXiangShan/NEMU PR #689 on 2024-11-27 — awaiting tagged release

https://github.com/OpenXiangShan/NEMU/pull/689
Web page

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

https://github.com/OpenXiangShan/NEMU/issues/681
Web page

Redirecting to isa v20260120

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 20× in last 7d / 76× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 358 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 261 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 10:29 UTCEG score recompute
  2. 2026-11-02 10:29 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  4. 2026-11-01 09:49 UTCEG score recompute
  5. 2026-11-01 09:49 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  6. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  7. 2026-10-31 09:10 UTCEG score recompute
  8. 2026-10-31 09:10 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  10. 2026-10-30 08:31 UTCEG score recompute
  11. 2026-10-30 08:31 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  13. 2026-10-29 07:52 UTCEG score recompute
  14. 2026-10-29 07:52 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  16. 2026-10-28 07:13 UTCEG score recompute
  17. 2026-10-28 07:13 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  19. 2026-10-27 06:34 UTCEG score recompute
  20. 2026-10-27 06:34 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  22. 2026-10-26 02:08 UTCEG score recompute
  23. 2026-10-26 02:08 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  25. 2026-10-25 14:37 UTCEG score recompute
Show 72 more
  1. 2026-10-25 01:28 UTCEG score recompute
  2. 2026-10-25 01:28 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  4. 2026-10-24 00:49 UTCEG score recompute
  5. 2026-10-24 00:49 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  6. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  7. 2026-10-23 00:09 UTCEG score recompute
  8. 2026-10-23 00:09 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  10. 2026-10-21 23:28 UTCEG score recompute
  11. 2026-10-21 23:28 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  13. 2026-10-20 22:44 UTCEG score recompute
  14. 2026-10-20 22:44 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  16. 2026-10-19 22:01 UTCEG score recompute
  17. 2026-10-19 22:00 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  19. 2026-10-18 20:51 UTCEG score recompute
  20. 2026-10-18 20:50 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  22. 2026-10-18 03:49 UTCEG score recompute
  23. 2026-10-17 20:01 UTCEG score recompute
  24. 2026-10-17 20:01 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  26. 2026-10-16 19:20 UTCEG score recompute
  27. 2026-10-16 19:20 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  28. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  29. 2026-10-15 16:54 UTCEG score recompute
  30. 2026-10-15 16:54 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  31. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  32. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  33. 2026-10-14 10:50 UTCEG score recompute
  34. 2026-10-14 10:50 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  35. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  36. 2026-10-13 09:32 UTCEG score recompute
  37. 2026-10-13 09:32 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  38. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  39. 2026-10-12 16:16 UTCEG score recompute
  40. 2026-10-12 08:44 UTCGHSA enrichmentGHSA-p786-pp8p-8p3m · GitHub severity CRITICAL · GitHub CVSS 9.8
  41. 2026-10-11 19:58 UTCEG score recompute
  42. 2026-10-11 17:11 UTCEG score recompute
  43. 2026-10-11 14:41 UTCEG score recompute
  44. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  45. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  46. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  47. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  48. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  49. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  50. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  51. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  52. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  53. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  54. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  55. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  56. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  57. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  58. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  59. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  60. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  61. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  62. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  63. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  64. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  65. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  66. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  67. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  68. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  69. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  70. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  71. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  72. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.4% · 37th percentile

Frequently asked(5)

What is CVE-2026-29649?
CVE-2026-29649 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-29649 published?
The CVE record for CVE-2026-29649 was published on April 20, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of April 24, 2026; the record at its source may have been updated since.
Is CVE-2026-29649 actively exploited?
CVE-2026-29649 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (38th percentile of EPSS-scored CVEs).
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?
An upstream fix for CVE-2026-29649 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix.

Dependency Blast Radius

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