{"id":"UBUNTU-CVE-2026-103262","details":"Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTTPClient that allows remote attackers to cause denial of service by sending a compressed response. Attackers can send a gzip-encoded decompression bomb that accumulates in memory without size limits, causing the application process to be killed by out-of-memory conditions.","modified":"2026-10-22T23:21:30.175103133Z","published":"2026-10-01T11:17:00Z","related":["USN-8952-1"],"upstream":["CVE-2026-103262"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-103262"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-103262"},{"type":"REPORT","url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-chx6-46f5-w4vp"},{"type":"REPORT","url":"https://github.com/tornadoweb/tornado/commit/e412435febba4569c552c5c9054f1bf92bd171a9"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-curlasynchttpclient"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8952-1"}],"affected":[{"package":{"name":"python-tornado","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/python-tornado?arch=source&distro=esm-infra-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.1-1ubuntu3.1+esm4"}]}],"versions":["4.2.1-1ubuntu2","4.2.1-1ubuntu3","4.2.1-1ubuntu3.1","4.2.1-1ubuntu3.1+esm1","4.2.1-1ubuntu3.1+esm2","4.2.1-1ubuntu3.1+esm3"],"ecosystem_specific":{"binaries":[{"binary_name":"python-tornado","binary_version":"4.2.1-1ubuntu3.1+esm4"},{"binary_version":"4.2.1-1ubuntu3.1+esm4","binary_name":"python3-tornado"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-103262.json"}},{"package":{"name":"python-tornado","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/python-tornado?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.5.3-1ubuntu0.2+esm4"}]}],"versions":["4.5.1-2.1~build2","4.5.2-1","4.5.3-1","4.5.3-1ubuntu0.1","4.5.3-1ubuntu0.2","4.5.3-1ubuntu0.2+esm1","4.5.3-1ubuntu0.2+esm2","4.5.3-1ubuntu0.2+esm3"],"ecosystem_specific":{"binaries":[{"binary_name":"python-tornado","binary_version":"4.5.3-1ubuntu0.2+esm4"},{"binary_name":"python3-tornado","binary_version":"4.5.3-1ubuntu0.2+esm4"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-103262.json"}},{"package":{"name":"python-tornado","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/python-tornado?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.1.0-1build1","6.1.0-2","6.1.0-3","6.1.0-3build1","6.1.0-3ubuntu0.1~esm1","6.1.0-3ubuntu0.1~esm2","6.1.0-3ubuntu0.1~esm4","6.1.0-3ubuntu0.1~esm5","6.1.0-3ubuntu0.1~esm6"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-tornado","binary_version":"6.1.0-3ubuntu0.1~esm6"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-103262.json"}},{"package":{"name":"python-tornado","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-tornado?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.4.0-1ubuntu0.6"}]}],"versions":["6.3.2-1","6.4.0-0ubuntu1","6.4.0-1","6.4.0-1build1","6.4.0-1ubuntu0.1","6.4.0-1ubuntu0.2","6.4.0-1ubuntu0.4","6.4.0-1ubuntu0.5"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"python3-tornado","binary_version":"6.4.0-1ubuntu0.6"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-103262.json"}},{"package":{"name":"python-tornado","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-tornado?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.5.4-0.1ubuntu0.2"}]}],"versions":["6.4.2-3","6.5.2-3","6.5.4-0.1","6.5.4-0.1ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_version":"6.5.4-0.1ubuntu0.2","binary_name":"python3-tornado"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-103262.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}