{"id":"UBUNTU-CVE-2026-115778","details":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.conch.telnet.Telnet.dataReceived appends every byte received after IAC SB to a persistent subnegotiation buffer until IAC SE is received, without applying a maximum length. Telnet option negotiation occurs before authentication, so an unauthenticated peer can omit the terminator and continuously grow the buffer. The resulting memory exhaustion can terminate the process and every service it hosts. This issue is fixed in version 26.10.0rc1.","modified":"2026-10-27T04:17:49.394457224Z","published":"2026-10-26T00:00:00Z","upstream":["CVE-2026-115778"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-115778"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-115778"},{"type":"REPORT","url":"https://github.com/twisted/twisted/commit/073ba878c6c07d569cb61abc5ae76d46eff1b529"},{"type":"REPORT","url":"https://github.com/twisted/twisted/commit/5d91cc66a3591faba758a80a1479e0103602facc"},{"type":"REPORT","url":"https://github.com/twisted/twisted/pull/12750"},{"type":"REPORT","url":"https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1"},{"type":"REPORT","url":"https://github.com/twisted/twisted/security/advisories/GHSA-cwm5-jh59-mwxr"}],"affected":[{"package":{"name":"twisted","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/twisted?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["13.0.0-1ubuntu1","13.2.0-1ubuntu1","13.2.0-1ubuntu1.2","13.2.0-1ubuntu1.2+esm1","13.2.0-1ubuntu1.2+esm2","13.2.0-1ubuntu1.2+esm3"],"ecosystem_specific":{"binaries":[{"binary_name":"python-twisted","binary_version":"13.2.0-1ubuntu1.2+esm3"},{"binary_name":"python-twisted-bin","binary_version":"13.2.0-1ubuntu1.2+esm3"},{"binary_version":"1:13.2.0-1ubuntu1.2+esm3","binary_name":"python-twisted-conch"},{"binary_version":"13.2.0-1ubuntu1.2+esm3","binary_name":"python-twisted-core"},{"binary_version":"13.2.0-1ubuntu1.2+esm3","binary_name":"python-twisted-lore"},{"binary_version":"13.2.0-1ubuntu1.2+esm3","binary_name":"python-twisted-mail"},{"binary_version":"13.2.0-1ubuntu1.2+esm3","binary_name":"python-twisted-names"},{"binary_name":"python-twisted-news","binary_version":"13.2.0-1ubuntu1.2+esm3"},{"binary_name":"python-twisted-runner","binary_version":"13.2.0-1ubuntu1.2+esm3"},{"binary_name":"python-twisted-web","binary_version":"13.2.0-1ubuntu1.2+esm3"},{"binary_name":"python-twisted-words","binary_version":"13.2.0-1ubuntu1.2+esm3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-115778.json"}},{"package":{"name":"twisted","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/twisted?arch=source&distro=esm-infra%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["15.2.1-1ubuntu2","15.5.0-1","15.5.0-2","15.5.0-2ubuntu1","15.5.0-4","16.0.0~pre1-1","16.0.0~pre1-1ubuntu1","16.0.0~pre1-2ubuntu1","16.0.0~pre1-3","16.0.0-1","16.0.0-1ubuntu0.2","16.0.0-1ubuntu0.4","16.0.0-1ubuntu0.4+esm1","16.0.0-1ubuntu0.4+esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"16.0.0-1ubuntu0.4+esm2","binary_name":"python-twisted"},{"binary_name":"python-twisted-bin","binary_version":"16.0.0-1ubuntu0.4+esm2"},{"binary_name":"python-twisted-conch","binary_version":"1:16.0.0-1ubuntu0.4+esm2"},{"binary_version":"16.0.0-1ubuntu0.4+esm2","binary_name":"python-twisted-core"},{"binary_name":"python-twisted-mail","binary_version":"16.0.0-1ubuntu0.4+esm2"},{"binary_name":"python-twisted-names","binary_version":"16.0.0-1ubuntu0.4+esm2"},{"binary_version":"16.0.0-1ubuntu0.4+esm2","binary_name":"python-twisted-news"},{"binary_name":"python-twisted-runner","binary_version":"16.0.0-1ubuntu0.4+esm2"},{"binary_version":"16.0.0-1ubuntu0.4+esm2","binary_name":"python-twisted-web"},{"binary_name":"python-twisted-words","binary_version":"16.0.0-1ubuntu0.4+esm2"},{"binary_name":"python3-twisted","binary_version":"16.0.0-1ubuntu0.4+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-115778.json"}},{"package":{"name":"twisted","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/twisted?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["16.6.0-2ubuntu3","17.9.0-1","17.9.0-2","17.9.0-2ubuntu0.1","17.9.0-2ubuntu0.3","17.9.0-2ubuntu0.3+esm1","17.9.0-2ubuntu0.3+esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"17.9.0-2ubuntu0.3+esm2","binary_name":"python-twisted"},{"binary_version":"17.9.0-2ubuntu0.3+esm2","binary_name":"python-twisted-bin"},{"binary_version":"1:17.9.0-2ubuntu0.3+esm2","binary_name":"python-twisted-conch"},{"binary_version":"17.9.0-2ubuntu0.3+esm2","binary_name":"python-twisted-core"},{"binary_name":"python-twisted-mail","binary_version":"17.9.0-2ubuntu0.3+esm2"},{"binary_name":"python-twisted-names","binary_version":"17.9.0-2ubuntu0.3+esm2"},{"binary_version":"17.9.0-2ubuntu0.3+esm2","binary_name":"python-twisted-news"},{"binary_name":"python-twisted-runner","binary_version":"17.9.0-2ubuntu0.3+esm2"},{"binary_name":"python-twisted-web","binary_version":"17.9.0-2ubuntu0.3+esm2"},{"binary_name":"python-twisted-words","binary_version":"17.9.0-2ubuntu0.3+esm2"},{"binary_name":"python3-twisted","binary_version":"17.9.0-2ubuntu0.3+esm2"},{"binary_version":"17.9.0-2ubuntu0.3+esm2","binary_name":"pyt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