CVE-2026-89134

CRITICALNVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory published 2026-09-27. NVD baseline CVSS 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
9.1EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 9.1Exploit: 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.

A certificate with no dNSName SAN but another SAN type present (e.g. registeredID or iPAddress) bypassed the Subject CN dNSName name-constraint check. The CN-as-DNS fallback was gated on cert->subjectCN != NULL && cert->altNames == NULL && !cert->isCA instead of "no dNSName SAN", so an out-of-scope CN was accepted. This incomplete fix from CVE-2026-6731, leading to the name-constraint check issue, was introduced in wolfSSL version 5.9.2.

CVSS v3
9.1
EG Score
9.1CRITICALhigh confidence
EG Risk
56
EG Risk 56/100CISA 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
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: An upstream fix is merged but not yet in a tagged release. 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 until it ships, then apply the release.
EPSS PROB
0.2%
EPSS %ILE
4th
KEV
Not listed

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

An upstream fix is merged but not yet in a tagged release. 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 until it ships, then apply the release.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). 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 27, 2026

Last Modified

October 2, 2026

Advisory Details (1)

Auto-updated Sep 27, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
github_pr

DNS name constraint fix

Fix merged in wolfSSL/wolfssl PR #10837 on 2026-07-08 — awaiting tagged release

https://github.com/wolfSSL/wolfssl/pull/10837

Vendor Advisories for CVE-2026-89134(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 31× in last 7d / 34× 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. 2026-10-04 09:47 UTCGHSA enrichment
  2. 2026-10-04 05:54 UTCGHSA enrichment
  3. 2026-10-04 02:03 UTCGHSA enrichment
  4. 2026-10-03 22:12 UTCGHSA enrichment
  5. 2026-10-03 18:20 UTCEG score recompute
  6. 2026-10-03 18:19 UTCGHSA enrichment
  7. 2026-10-03 14:18 UTCGHSA enrichment
  8. 2026-10-03 10:26 UTCGHSA enrichment
  9. 2026-10-03 06:35 UTCGHSA enrichment
  10. 2026-10-03 02:43 UTCGHSA enrichment
  11. 2026-10-02 22:52 UTCEG score recompute
  12. 2026-10-02 22:52 UTCGHSA enrichment
  13. 2026-10-02 19:00 UTCEG score recompute▲ 2.80
  14. 2026-10-02 19:00 UTCGHSA enrichment
  15. 2026-10-02 18:59 UTCNVD updateCVSS v3 → 9.1 · severity → CRITICAL
  16. 2026-10-01 20:30 UTCEG score recompute
  17. 2026-10-01 20:30 UTCGHSA enrichment
  18. 2026-10-01 19:51 UTCEPSS rescore
  19. 2026-09-30 18:59 UTCEG score recompute
  20. 2026-09-30 18:59 UTCGHSA enrichment
  21. 2026-09-30 15:04 UTCEPSS rescore
  22. 2026-09-29 17:36 UTCEG score recompute
  23. 2026-09-29 17:36 UTCGHSA enrichment
  24. 2026-09-29 16:46 UTCEG score recompute
  25. 2026-09-29 16:45 UTCGHSA enrichment
Show 9 more
  1. 2026-09-28 20:50 UTCEG score recompute
  2. 2026-09-28 20:50 UTCGHSA enrichment
  3. 2026-09-28 13:52 UTCEPSS rescore
  4. 2026-09-28 11:43 UTCEG score recompute
  5. 2026-09-28 11:43 UTCGHSA enrichment
  6. 2026-09-27 13:48 UTCEPSS rescore
  7. 2026-09-27 10:20 UTCEG score recompute
  8. 2026-09-27 09:20 UTCEG score recompute
  9. 2026-09-27 09:20 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-89134?
CVE-2026-89134 is a critical vulnerability published on September 27, 2026. A certificate with no dNSName SAN but another SAN type present (e.g. registeredID or iPAddress) bypassed the Subject CN dNSName name-constraint check. The CN-as-DNS fallback was gated on cert->subjectCN != NULL && cert->altNames == NULL && !cert->isCA instead of "no dNSName SAN", so an out-of-scope…
When was CVE-2026-89134 disclosed?
CVE-2026-89134 was first published on September 27, 2026, with the most recent update on October 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-89134 actively exploited?
CVE-2026-89134 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (4th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-89134?
CVE-2026-89134 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-89134?
An upstream fix for CVE-2026-89134 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. The vendor advisories EchelonGraph has for CVE-2026-89134 are linked in the Vendor Advisories panel on this page.

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