CVE-2026-90191

HIGHPre-NVD 8.48.4—
EchelonGraph scoreHIGH confidence

Score 8.4 from GitHub Security Advisory (severity: HIGH) published 2026-09-17. A secondary CVSS source baseline 8.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
8.4EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 8.4Exploit: None knownExposed services: Not assessed

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

In the Linux kernel, the following vulnerability has been resolved:

mailbox: riscv-sbi-mpxy: validate RPMI notification lengths

The SBI return value controls how many bytes are copied from shared memory into the RPMI notification buffer. It is not validated against the negotiated shared-memory size before that copy. The event walker also uses a reversed loop condition and can inspect a short event record.

Validate the complete notification length before copying it, iterate only while a full event header remains, and stop when a declared event payload extends beyond the copied notification data.

CVSS v3
8.4
EG Score
8.4HIGHhigh confidence
EG Risk
42
EG Risk 42/100CISA SSVC

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
Severity84% × 45%
Exploitation0% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.2%
EPSS %ILE
8th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 17, 2026

Last Modified

September 18, 2026

Advisory Details (3)

Auto-updated Sep 18, 2026
No patch confirmed yet.
generic

mailbox: riscv-sbi-mpxy: validate RPMI notification lengths - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/11d5af151bcbe78f5a579e0faecd3be9cea0399a
generic

mailbox: riscv-sbi-mpxy: validate RPMI notification lengths - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76
generic

mailbox: riscv-sbi-mpxy: validate RPMI notification lengths - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b

Vendor Advisories for CVE-2026-90191(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (178 versions)
  • every version up to 7.2.6-1: fixed in 7.2.6-1
—

Data Freshness Timeline

(refreshed 27× in last 7d / 71× 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.

  1. 2026-10-05 10:28 UTCEG score recompute
  2. 2026-10-05 10:28 UTCGHSA enrichment
  3. 2026-10-04 23:22 UTCEPSS rescore
  4. 2026-10-04 22:00 UTCGHSA enrichment
  5. 2026-10-04 09:33 UTCGHSA enrichment
  6. 2026-10-03 21:04 UTCEG score recompute
  7. 2026-10-03 21:04 UTCGHSA enrichment
  8. 2026-10-03 08:36 UTCGHSA enrichment
  9. 2026-10-02 19:56 UTCEG score recompute
  10. 2026-10-02 19:56 UTCGHSA enrichment
  11. 2026-10-02 07:28 UTCEG score recompute
  12. 2026-10-02 07:28 UTCGHSA enrichment
  13. 2026-10-01 19:51 UTCEPSS rescore
  14. 2026-10-01 19:00 UTCGHSA enrichment
  15. 2026-10-01 06:31 UTCGHSA enrichment
  16. 2026-09-30 18:03 UTCEG score recompute
  17. 2026-09-30 18:03 UTCGHSA enrichment
  18. 2026-09-30 15:04 UTCEPSS rescore
  19. 2026-09-30 05:20 UTCGHSA enrichment
  20. 2026-09-29 16:51 UTCEG score recompute
  21. 2026-09-29 16:50 UTCGHSA enrichment
  22. 2026-09-29 04:23 UTCEG score recompute
  23. 2026-09-29 04:23 UTCGHSA enrichment
  24. 2026-09-28 15:55 UTCEG score recompute
  25. 2026-09-28 15:55 UTCGHSA enrichment
Show 46 more
  1. 2026-09-28 13:52 UTCEPSS rescore
  2. 2026-09-28 13:52 UTCEPSS rescore
  3. 2026-09-28 03:28 UTCGHSA enrichment
  4. 2026-09-27 15:00 UTCEG score recompute
  5. 2026-09-27 15:00 UTCGHSA enrichment
  6. 2026-09-27 13:49 UTCEPSS rescore
  7. 2026-09-27 02:32 UTCEG score recompute
  8. 2026-09-27 02:32 UTCGHSA enrichment
  9. 2026-09-26 15:59 UTCEPSS rescore
  10. 2026-09-26 14:04 UTCGHSA enrichment
  11. 2026-09-26 01:08 UTCEG score recompute
  12. 2026-09-26 01:08 UTCGHSA enrichment
  13. 2026-09-25 12:38 UTCGHSA enrichment
  14. 2026-09-25 00:11 UTCEG score recompute
  15. 2026-09-25 00:11 UTCGHSA enrichment
  16. 2026-09-24 14:04 UTCEPSS rescore
  17. 2026-09-24 11:43 UTCGHSA enrichment
  18. 2026-09-23 23:16 UTCEG score recompute
  19. 2026-09-23 23:15 UTCGHSA enrichment
  20. 2026-09-23 17:54 UTCEPSS rescore
  21. 2026-09-23 10:45 UTCGHSA enrichment
  22. 2026-09-22 22:14 UTCEG score recompute
  23. 2026-09-22 22:14 UTCGHSA enrichment
  24. 2026-09-22 16:01 UTCEPSS rescore
  25. 2026-09-22 09:46 UTCGHSA enrichment
  26. 2026-09-21 21:19 UTCEG score recompute
  27. 2026-09-21 21:19 UTCGHSA enrichment
  28. 2026-09-21 21:09 UTCEPSS rescore
  29. 2026-09-21 08:51 UTCGHSA enrichment
  30. 2026-09-20 20:24 UTCEG score recompute
  31. 2026-09-20 20:24 UTCGHSA enrichment
  32. 2026-09-20 20:16 UTCEPSS rescore
  33. 2026-09-20 07:56 UTCGHSA enrichment
  34. 2026-09-19 19:27 UTCEG score recompute
  35. 2026-09-19 19:27 UTCGHSA enrichment
  36. 2026-09-19 06:59 UTCEG score recompute
  37. 2026-09-19 06:59 UTCGHSA enrichment
  38. 2026-09-18 19:28 UTCEPSS rescore
  39. 2026-09-18 18:31 UTCEG score recompute
  40. 2026-09-18 18:31 UTCGHSA enrichment
  41. 2026-09-18 18:05 UTCEG score recompute▲ 8.40
  42. 2026-09-18 18:04 UTCGHSA enrichment
  43. 2026-09-18 17:59 UTCMITRE cvelistV5CVSS v3 → 8.4 · severity → HIGH
  44. 2026-09-17 17:23 UTCNVD update
  45. 2026-09-17 16:42 UTCEG score recompute
  46. 2026-09-17 16:19 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-90191?
CVE-2026-90191 is a high vulnerability published on September 17, 2026. In the Linux kernel, the following vulnerability has been resolved: mailbox: riscv-sbi-mpxy: validate RPMI notification lengths The SBI return value controls how many bytes are copied from shared memory into the RPMI notification buffer. It is not validated against the negotiated shared-memory size…
When was CVE-2026-90191 disclosed?
CVE-2026-90191 was first published on September 17, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-90191 actively exploited?
CVE-2026-90191 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (8th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-90191?
CVE-2026-90191 has a CVSS base score of 8.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-90191?
No fix for CVE-2026-90191 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-90191 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-90191

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