{"id":"CVE-2026-100665","title":"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","summary":"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 SSLEn…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-295"],"vendor":"netty","product":"netty","affected":["netty >= 4.2.11.Final < 4.2.18.Final"],"published":"2026-09-26","updated":"2026-10-02","sourceUpdated":"2026-10-02T16:16:41.803","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100665","references":[{"url":"https://github.com/netty/netty/commit/09e72c4fd8007277121ed48db63a124b112b96fe","label":"disclosure@vulncheck.com"},{"url":"https://github.com/netty/netty/commit/994e887ed9","label":"disclosure@vulncheck.com"},{"url":"https://github.com/netty/netty/security/advisories/GHSA-mj35-3qqm-q387","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/netty-4.2.11-through-4.2.17-quic-hostname-verification-bypass","label":"disclosure@vulncheck.com"},{"url":"https://github.com/netty/netty/security/advisories/GHSA-mj35-3qqm-q387","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100665.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-100665"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541820"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-100665"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100665"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-02T15:46:31.371553Z"},"epss":0.00367,"epssPercentile":0.30429,"ingestedAt":"2026-09-26T13:33:20.915Z","slug":"CVE-2026-100665","body":"## Overview\n\nNetty 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat OpenShift Dev Spaces · no fix planned: Red Hat OpenShift Dev Spaces · updated 2026-09-29 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100665.json)","depth":"midnight","depthScore":53,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":214980,"id":"CVE-2026-100665","ts":1790958213602,"field":"exploit_available","old":"false","new":"true"}]}