CVE-2026-29644

MEDIUMNVD 5.35.3
EchelonGraph scoreMEDIUM confidence

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

Score 5.3 from GitHub Security Advisory published 2026-04-21. NVD baseline CVSS 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-24131 (ENISA EUVD) · GHSA-p2hj-qw82-grpc (GitHub Security Advisories)Source: ENISA EUVD

5.3EG
EchelonGraph verdictMonitorThe 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, then apply it (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 5.3Exploit: 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.

XiangShan (open-source high-performance RISC-V processor) commit edb1dfaf7d290ae99724594507dc46c2c2125384 (2024-11-28) has improper gating of its distributed CSR write-enable path, allowing illegal CSR write attempts to alter custom PMA (Physical Memory Attribute) CSR state. Though the RISC-V privileged specification requires an illegal-instruction exception for non-existent/illegal CSR accesses, affected XiangShan versions may still propagate such writes to replicated PMA configuration state. Local attackers able to execute code on the core (privilege context depends on system integration) can exploit this to tamper with memory-attribute enforcement, potentially leading to privilege escalation, information disclosure, or denial of service depending on how PMA enforces platform security and isolation boundaries.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

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)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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, then apply it.
EPSS PROB
0.1%
EPSS %ILE
below the 1st
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 (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS. 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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 every mission impact level.

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, then apply it.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 days if the affected system is publicly exposed; Fix on system upgrade 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. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (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 21, 2026

Last Modified

April 21, 2026

Advisory Details (5)

Auto-updated Aug 2, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
Web page

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

https://github.com/OpenXiangShan/XiangShan/issues/3959
Web page

物理地址保护 - 香山 XiangShan

https://xiangshan-doc-test.readthedocs.io/next/memory/mmu/pmp_pma/
GitHub commit

commit edb1dfaf7d29 (OpenXiangShan/XiangShan)

Fix landed in OpenXiangShan/XiangShan commit edb1dfaf7d29 — awaiting tagged release

https://github.com/OpenXiangShan/XiangShan/commit/edb1dfaf7d290ae99724594507dc46c2c2125384
GitHub commit

commit 2b1f9796aa98 (OpenXiangShan/XiangShan)

Fix landed in OpenXiangShan/XiangShan commit 2b1f9796aa98 — awaiting tagged release

https://github.com/OpenXiangShan/XiangShan/commit/2b1f9796aa98597e5eeac32e5bb1418496987ca4

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 36× 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 96 of 217 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. 4 repeat rows among the latest 100 are merged into the row they repeat. The 121 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  2. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  3. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  4. 2026-10-30 23:25 UTCOSV refresh
  5. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  6. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  7. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  8. 2026-10-25 14:37 UTCEG score recompute
  9. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  10. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  11. 2026-10-23 03:56 UTCEG score recompute
  12. 2026-10-23 03:56 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  13. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  14. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  15. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  16. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  17. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  18. 2026-10-18 03:49 UTCEG score recompute
  19. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  20. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  21. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  22. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  23. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  24. 2026-10-12 16:16 UTCEG score recompute
  25. 2026-10-11 19:58 UTCEG score recompute
Show 71 more
  1. 2026-10-11 17:11 UTCEG score recompute
  2. 2026-10-11 14:41 UTCEG score recompute
  3. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  4. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  5. 2026-10-10 18:55 UTCOSV refresh
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  7. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  8. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  9. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  10. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  11. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  12. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  13. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  14. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  15. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  16. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  17. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  18. 2026-09-21 05:49 UTCOSV refresh
  19. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  20. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  21. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  22. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  23. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  24. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  25. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  26. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  27. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  28. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  29. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.1% · below the 1st percentile
  30. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  31. 2026-09-02 03:39 UTCOSV refresh
  32. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  33. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  34. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  35. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  36. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  37. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  38. 2026-08-24 14:17 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  39. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  40. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  41. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  42. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  43. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  44. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  45. 2026-08-16 06:19 UTCEG score recompute
  46. 2026-08-16 06:19 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  47. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  48. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  49. 2026-08-14 04:30 UTCEG score recompute
  50. 2026-08-14 04:30 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  51. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  52. 2026-08-12 18:40 UTCEG score recompute
  53. 2026-08-12 18:40 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  54. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  55. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  56. 2026-08-11 08:24 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  57. 2026-08-10 06:00 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  58. 2026-08-09 03:42 UTCEG score recompute
  59. 2026-08-09 03:42 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  60. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  61. 2026-08-07 12:59 UTCEG score recompute
  62. 2026-08-07 12:59 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  63. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  64. 2026-08-05 23:11 UTCEG score recompute
  65. 2026-08-05 23:11 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  66. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  67. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  68. 2026-08-03 21:24 UTCEG score recompute
  69. 2026-08-03 21:24 UTCGHSA enrichmentGHSA-p2hj-qw82-grpc · GitHub CVSS 5.3
  70. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  71. 2026-08-02 12:49 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-29644?
CVE-2026-29644 is a medium-severity vulnerability; its CVE record was published on April 21, 2026. XiangShan (open-source high-performance RISC-V processor) commit edb1dfaf7d290ae99724594507dc46c2c2125384 (2024-11-28) has improper gating of its distributed CSR write-enable path, allowing illegal CSR write attempts to alter custom PMA (Physical Memory Attribute) CSR state. Though the RISC-V…
When was the CVE record for CVE-2026-29644 published?
The CVE record for CVE-2026-29644 was published on April 21, 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 21, 2026; the record at its source may have been updated since.
Is CVE-2026-29644 actively exploited?
CVE-2026-29644 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (below the 1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-29644?
CVE-2026-29644 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-29644?
An upstream fix for CVE-2026-29644 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

Explore the affected products and dependency analysis for CVE-2026-29644

Explore →

Is Your Infrastructure Affected by CVE-2026-29644?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.