{"id":"UBUNTU-CVE-2026-47244","details":"Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, DefaultHttp2Connection.DefaultEndpoint initialises maxActiveStreams/maxStreams to Integer.MAX_VALUE, and Http2Settings never inserts SETTINGS_MAX_CONCURRENT_STREAMS by default (Http2Settings.java:305-307 only clamps a user-supplied value). Unless the application explicitly calls initialSettings().maxConcurrentStreams(n), a Netty HTTP/2 server advertises no limit and enforces none locally. Each open stream allocates a DefaultStream object, PropertyMap slots, flow-controller state and IntObjectHashMap entry; with ~2^30 permissible odd stream IDs a single TCP connection can create hundreds of thousands of long-lived stream objects. This is also the precondition for CVE-2023-44487-style Rapid-Reset amplification, where the absence of a low concurrent cap multiplies backend work. Versions 4.1.135.Final and 4.2.15.Final patch the issue.","modified":"2026-09-10T16:30:29.285715718Z","published":"2026-06-12T15:16:00Z","upstream":["CVE-2026-47244"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-47244"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-47244"},{"type":"REPORT","url":"https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6q"},{"type":"REPORT","url":"https://github.com/netty/netty/releases/tag/netty-4.1.135.Final"},{"type":"REPORT","url":"https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"}],"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-2026-47244.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-2026-47244.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-2026-47244.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_version":"1:4.1.45-1ubuntu0.1~esm7","binary_name":"libnetty-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47244.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_name":"libnetty-java","binary_version":"1:4.1.48-4+deb11u2ubuntu0.2+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47244.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-2026-47244.json"}},{"package":{"name":"netty","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/netty?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-10","1:4.1.48-10ubuntu0.25.10.1","1:4.1.48-10ubuntu0.25.10.2"],"ecosystem_specific":{"binaries":[{"binary_name":"libnetty-java","binary_version":"1:4.1.48-10ubuntu0.25.10.2"}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