CVE-2026-100665

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 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-25)

CWE

CWE-295

Published

2026-09-26

Modified

2026-10-02

Record from

the NVD, synced 2026-10-19

References

• https://github.com/netty/netty/commit/09e72c4fd8007277121ed48db63a124b112b96fe
• https://github.com/netty/netty/commit/994e887ed9
• https://github.com/netty/netty/security/advisories/GHSA-mj35-3qqm-q387
• https://www.vulncheck.com/advisories/netty-4.2.11-through-4.2.17-quic-hostname-verification-bypass
• https://github.com/netty/netty/security/advisories/GHSA-mj35-3qqm-q387

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