{"id":"UBUNTU-CVE-2026-58055","details":"nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.","modified":"2026-07-02T18:03:26.175084971Z","published":"2026-06-28T02:16:00Z","related":["USN-8495-1"],"upstream":["CVE-2026-58055"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-58055"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-58055"},{"type":"REPORT","url":"https://github.com/bikini/exploitarium/tree/main/nghttp2-nghttpx-upgrade-queue-poison-poc"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/nghttp2-nghttpx-http-request-response-smuggling-via-upgrade-request-with-content-length"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8495-1"}],"affected":[{"package":{"name":"nghttp2","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/nghttp2?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.6.7-1","1.3.4-2","1.4.0-1","1.4.0-2","1.5.0-2","1.6.0-1","1.7.0-1","1.7.1-1","1.7.1-1ubuntu0.1~esm1","1.7.1-1ubuntu0.1~esm2","1.7.1-1ubuntu0.1~esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.7.1-1ubuntu0.1~esm3","binary_name":"libnghttp2-14"},{"binary_name":"nghttp2","binary_version":"1.7.1-1ubuntu0.1~esm3"},{"binary_name":"nghttp2-client","binary_version":"1.7.1-1ubuntu0.1~esm3"},{"binary_name":"nghttp2-proxy","binary_version":"1.7.1-1ubuntu0.1~esm3"},{"binary_name":"nghttp2-server","binary_version":"1.7.1-1ubuntu0.1~esm3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58055.json"}},{"package":{"name":"nghttp2","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/nghttp2?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.25.0-1","1.27.0-1","1.28.0-1","1.29.0-1","1.29.0-1build1","1.30.0-1","1.30.0-1ubuntu1","1.30.0-1ubuntu1+esm1","1.30.0-1ubuntu1+esm2","1.30.0-1ubuntu1+esm3"],"ecosystem_specific":{"binaries":[{"binary_name":"libnghttp2-14","binary_version":"1.30.0-1ubuntu1+esm3"},{"binary_name":"nghttp2","binary_version":"1.30.0-1ubuntu1+esm3"},{"binary_version":"1.30.0-1ubuntu1+esm3","binary_name":"nghttp2-client"},{"binary_name":"nghttp2-proxy","binary_version":"1.30.0-1ubuntu1+esm3"},{"binary_version":"1.30.0-1ubuntu1+esm3","binary_name":"nghttp2-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58055.json"}},{"package":{"name":"nghttp2","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/nghttp2?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.39.2-1","1.40.0-1","1.40.0-1build1","1.40.0-1ubuntu0.1","1.40.0-1ubuntu0.2","1.40.0-1ubuntu0.3","1.40.0-1ubuntu0.3+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnghttp2-14","binary_version":"1.40.0-1ubuntu0.3+esm1"},{"binary_name":"nghttp2","binary_version":"1.40.0-1ubuntu0.3+esm1"},{"binary_name":"nghttp2-client","binary_version":"1.40.0-1ubuntu0.3+esm1"},{"binary_version":"1.40.0-1ubuntu0.3+esm1","binary_name":"nghttp2-proxy"},{"binary_version":"1.40.0-1ubuntu0.3+esm1","binary_name":"nghttp2-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58055.json"}},{"package":{"name":"nghttp2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/nghttp2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.43.0-1ubuntu0.4"}]}],"versions":["1.43.0-1","1.43.0-1build1","1.43.0-1build2","1.43.0-1build3","1.43.0-1ubuntu0.1","1.43.0-1ubuntu0.2","1.43.0-1ubuntu0.3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.43.0-1ubuntu0.4","binary_name":"libnghttp2-14"},{"binary_version":"1.43.0-1ubuntu0.4","binary_name":"nghttp2"},{"binary_name":"nghttp2-client","binary_version":"1.43.0-1ubuntu0.4"},{"binary_name":"nghttp2-proxy","binary_version":"1.43.0-1ubuntu0.4"},{"binary_version":"1.43.0-1ubuntu0.4","binary_name":"nghttp2-server"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58055.json"}},{"package":{"name":"nghttp2","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/nghttp2?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.59.0-1ubuntu0.4"}]}],"versions":["1.55.1-1","1.57.0-1","1.58.0-1","1.59.0-1","1.59.0-1build1","1.59.0-1build2","1.59.0-1build4","1.59.0-1ubuntu0.1","1.59.0-1ubuntu0.2","1.59.0-1ubuntu0.3"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"libnghttp2-14","binary_version":"1.59.0-1ubuntu0.4"},{"binary_version":"1.59.0-1ubuntu0.4","binary_name":"nghttp2"},{"binary_name":"nghttp2-client","binary_version":"1.59.0-1ubuntu0.4"},{"binary_name":"nghttp2-proxy","binary_version":"1.59.0-1ubuntu0.4"},{"binary_name":"nghttp2-server","binary_version":"1.59.0-1ubuntu0.4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58055.json"}},{"package":{"name":"nghttp2","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/nghttp2?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.64.0-1.1ubuntu1.2"}]}],"versions":["1.64.0-1ubuntu1","1.64.0-1.1","1.64.0-1.1build1","1.64.0-1.1ubuntu1","1.64.0-1.1ubuntu1.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnghttp2-14","binary_version":"1.64.0-1.1ubuntu1.2"},{"binary_name":"nghttp2","binary_version":"1.64.0-1.1ubuntu1.2"},{"binary_name":"nghttp2-client","binary_version":"1.64.0-1.1ubuntu1.2"},{"binary_version":"1.64.0-1.1ubuntu1.2","binary_name":"nghttp2-proxy"},{"binary_name":"nghttp2-server","binary_version":"1.64.0-1.1ubuntu1.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58055.json"}},{"package":{"name":"nghttp2","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/nghttp2?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.68.0-2ubuntu0.2"}]}],"versions":["1.64.0-1.1ubuntu1","1.64.0-1.1ubuntu2","1.68.0-1","1.68.0-2","1.68.0-2ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnghttp2-14","binary_version":"1.68.0-2ubuntu0.2"},{"binary_version":"1.68.0-2ubuntu0.2","binary_name":"nghttp2"},{"binary_name":"nghttp2-client","binary_version":"1.68.0-2ubuntu0.2"},{"binary_name":"nghttp2-proxy","binary_version":"1.68.0-2ubuntu0.2"},{"binary_name":"nghttp2-server","binary_version":"1.68.0-2ubuntu0.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58055.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N"},{"type":"Ubuntu","score":"medium"}]}