{"id":"UBUNTU-CVE-2026-75595","details":"Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Fina and 4.2.17.Final, io.netty.handler.ssl.SslClientHelloHandler#decode checks the wrong offset before reading the four-byte TLS handshake header, so a ClientHello whose handshake header spans records can cause an IndexOutOfBoundsException and invoke select(ctx, null). This selects the default SslContext instead of the SNI-specific context. In deployments where per-SNI clientAuth=REQUIRE is the sole mutual TLS gate, the default SslContext uses clientAuth=NONE or clientAuth=OPTIONAL, and no application-layer certificate verification exists, an unauthenticated remote attacker can bypass the protected route's mutual TLS requirement. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.","modified":"2026-09-10T16:30:32.586432984Z","published":"2026-08-19T21:17:00Z","upstream":["CVE-2026-75595"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-75595"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-75595"},{"type":"REPORT","url":"https://github.com/netty/netty/security/advisories/GHSA-fccg-mwvh-qqg4"},{"type":"REPORT","url":"https://github.com/netty/netty/pull/17213"},{"type":"REPORT","url":"https://github.com/netty/netty/pull/17217"},{"type":"REPORT","url":"https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7"},{"type":"REPORT","url":"https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961"},{"type":"REPORT","url":"https://github.com/netty/netty/releases/tag/netty-4.1.137.Final"},{"type":"REPORT","url":"https://github.com/netty/netty/releases/tag/netty-4.2.17.Final"},{"type":"REPORT","url":"https://github.com/netty/netty/security/advisories/GHSA-c4c3-7fpv-j4q5"}],"affected":[{"package":{"name":"netty","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/netty?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:3.2.6.Final-2","1:3.2.6.Final-2+deb8u2build0.14.04.1~esm1","1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnetty-java","binary_version":"1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-75595.json"}},{"package":{"name":"netty","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/netty?arch=source&distro=esm-apps-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:3.2.6.Final-2","1:4.0.32-1","1:4.0.33-1","1:4.0.34-1","1:4.0.34-1ubuntu0.1~esm1","1:4.0.34-1ubuntu0.1~esm2","1:4.0.34-1ubuntu0.1~esm3","1:4.0.34-1ubuntu0.1~esm4","1:4.0.34-1ubuntu0.1~esm5"],"ecosystem_specific":{"binaries":[{"binary_name":"libnetty-java","binary_version":"1:4.0.34-1ubuntu0.1~esm5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-75595.json"}},{"package":{"name":"netty","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/netty?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.7-4","1:4.1.7-4ubuntu0.1~esm1","1:4.1.7-4ubuntu0.1","1:4.1.7-4ubuntu0.1+esm1","1:4.1.7-4ubuntu0.1+esm2","1:4.1.7-4ubuntu0.1+esm3","1:4.1.7-4ubuntu0.1+esm4","1:4.1.7-4ubuntu0.1+esm5","1:4.1.7-4ubuntu0.1+esm6","1:4.1.7-4ubuntu0.1+esm7"],"ecosystem_specific":{"binaries":[{"binary_name":"libnetty-java","binary_version":"1:4.1.7-4ubuntu0.1+esm7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-75595.json"}},{"package":{"name":"netty","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/netty?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.33-1","1:4.1.33-2","1:4.1.33-3","1:4.1.45-1","1:4.1.45-1ubuntu0.1~esm1","1:4.1.45-1ubuntu0.1~esm2","1:4.1.45-1ubuntu0.1~esm3","1:4.1.45-1ubuntu0.1~esm4","1:4.1.45-1ubuntu0.1~esm6","1:4.1.45-1ubuntu0.1~esm7"],"ecosystem_specific":{"binaries":[{"binary_name":"libnetty-java","binary_version":"1:4.1.45-1ubuntu0.1~esm7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-75595.json"}},{"package":{"name":"netty","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/netty?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-4","1:4.1.48-4+deb11u1build0.22.04.1","1:4.1.48-4+deb11u2build0.22.04.1","1:4.1.48-4+deb11u2ubuntu0.1~esm1","1:4.1.48-4+deb11u2ubuntu0.1~esm2","1:4.1.48-4+deb11u2ubuntu0.1","1:4.1.48-4+deb11u2ubuntu0.1+esm1","1:4.1.48-4+deb11u2ubuntu0.1+esm3","1:4.1.48-4+deb11u2ubuntu0.2","1:4.1.48-4+deb11u2ubuntu0.2+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1:4.1.48-4+deb11u2ubuntu0.2+esm1","binary_name":"libnetty-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-75595.json"}},{"package":{"name":"netty","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/netty?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-7","1:4.1.48-8","1:4.1.48-9","1:4.1.48-9ubuntu0.1~esm1","1:4.1.48-9ubuntu0.1~esm2","1:4.1.48-9ubuntu0.1","1:4.1.48-9ubuntu0.1+esm1","1:4.1.48-9ubuntu0.1+esm3","1:4.1.48-9ubuntu0.2","1:4.1.48-9ubuntu0.2+esm1","1:4.1.48-9ubuntu0.2+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"libnetty-java","binary_version":"1:4.1.48-9ubuntu0.2+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-75595.json"}},{"package":{"name":"netty","ecosystem":"Ubuntu:Pro:26.04:LTS","purl":"pkg:deb/ubuntu/netty?arch=source&distro=esm-apps%2Fresolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-10","1:4.1.48-11","1:4.1.48-12","1:4.1.48-13","1:4.1.48-14","1:4.1.48-16","1:4.1.48-16ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"libnetty-buffer-java","binary_version":"1:4.1.48-16ubuntu0.1~esm2"},{"binary_version":"1:4.1.48-16ubuntu0.1~esm2","binary_name":"libnetty-common-java"},{"binary_name":"libnetty-java","binary_version":"1:4.1.48-16ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-75595.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}