CVE-2026-100665

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-26. A secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Netty versions from 4.2.11.Final before 4.2.18.Final contain an incomplete hostname verification fix in the QUIC certificate verification path when using a plain X509TrustManager. The BoringSSLCertificateVerifyCallback discards the SSLEngine for plain trust managers, preventing endpoint identification from running even when HTTPS verification is configured. Attackers on the network path can present a certificate chain for the wrong hostname that the plain trust manager accepts, bypassing hostname authentication for QUIC clients.

CVSS v3
7.5
EG Score
7.5HIGHhigh confidence
EG Risk
65
EG Risk 65/100CISA 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
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
19th
KEV
Not listed

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

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (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 26, 2026

Last Modified

October 2, 2026

Advisory Details (4)

Auto-updated Sep 26, 2026
Patch available. Sources: github, github_commit.
generic

Netty 4.2.11 through 4.2.17 QUIC Hostname Verification Bypass | Advisories | VulnCheck

https://www.vulncheck.com/advisories/netty-4.2.11-through-4.2.17-quic-hostname-verification-bypass
github_commit Patch Available

commit 994e887ed9 (netty/netty)

Patch available: netty/netty netty-4.2.11.Final (contains commit 994e887ed9)

https://github.com/netty/netty/commit/994e887ed9
github_commit Patch Available

commit 09e72c4fd800 (netty/netty)

Patch available: netty/netty netty-4.1.135.Final (contains commit 09e72c4fd800)

https://github.com/netty/netty/commit/09e72c4fd8007277121ed48db63a124b112b96fe
github Patch Available

Incomplete fix for CVE-2026-50010: QUIC clients still bypass hostname verification with a plain X509TrustManager · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-mj35-3qqm-q387

Vendor Advisories for CVE-2026-100665(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 32× in last 7d / 38× 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 02:27 UTCGHSA enrichment
  2. 2026-10-03 15:08 UTCEG score recompute
  3. 2026-10-03 15:08 UTCGHSA enrichment
  4. 2026-10-03 14:25 UTCEPSS rescore
  5. 2026-10-03 03:48 UTCGHSA enrichment
  6. 2026-10-02 16:29 UTCEG score recompute
  7. 2026-10-02 16:28 UTCGHSA enrichment
  8. 2026-10-02 15:56 UTCEG score recompute
  9. 2026-10-02 15:56 UTCGHSA enrichment
  10. 2026-10-02 10:10 UTCGHSA enrichment
  11. 2026-10-01 22:52 UTCEG score recompute
  12. 2026-10-01 22:52 UTCGHSA enrichment
  13. 2026-10-01 19:49 UTCEPSS rescore
  14. 2026-10-01 11:34 UTCGHSA enrichment
  15. 2026-10-01 00:15 UTCEG score recompute
  16. 2026-10-01 00:15 UTCGHSA enrichment
  17. 2026-09-30 15:02 UTCEPSS rescore
  18. 2026-09-30 12:43 UTCGHSA enrichment
  19. 2026-09-30 01:25 UTCEG score recompute
  20. 2026-09-30 01:24 UTCGHSA enrichment
  21. 2026-09-29 15:20 UTCEPSS rescore
  22. 2026-09-29 14:04 UTCGHSA enrichment
  23. 2026-09-29 02:46 UTCEG score recompute
  24. 2026-09-29 02:46 UTCGHSA enrichment
  25. 2026-09-28 15:27 UTCEG score recompute
Show 13 more
  1. 2026-09-28 15:27 UTCGHSA enrichment
  2. 2026-09-28 13:50 UTCEPSS rescore
  3. 2026-09-28 04:45 UTCGHSA enrichment
  4. 2026-09-27 17:24 UTCEG score recompute
  5. 2026-09-27 17:24 UTCGHSA enrichment
  6. 2026-09-27 16:35 UTCEG score recompute
  7. 2026-09-27 16:35 UTCGHSA enrichment
  8. 2026-09-27 13:12 UTCGHSA enrichment
  9. 2026-09-27 01:54 UTCEG score recompute
  10. 2026-09-27 01:54 UTCGHSA enrichment
  11. 2026-09-26 14:33 UTCEG score recompute
  12. 2026-09-26 13:37 UTCEG score recompute
  13. 2026-09-26 13:30 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-100665?
CVE-2026-100665 is a high vulnerability published on September 26, 2026. Netty versions from 4.2.11.Final before 4.2.18.Final contain an incomplete hostname verification fix in the QUIC certificate verification path when using a plain X509TrustManager. The BoringSSLCertificateVerifyCallback discards the SSLEngine for plain trust managers, preventing endpoint…
When was CVE-2026-100665 disclosed?
CVE-2026-100665 was first published on September 26, 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-2026-100665 actively exploited?
CVE-2026-100665 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (19th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-100665?
CVE-2026-100665 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-100665?
A fix for CVE-2026-100665 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-100665 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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