{"id":"UBUNTU-CVE-2026-53583","details":"libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, verify_server_cert in src/libgit2/streams/openssl.c uses an inverted !!memcmp result in the GEN_IPADD branch when comparing an IP-literal host with a certificate IP SubjectAltName. OpenSSL builds reject matching IP addresses and accept mismatched IP addresses, allowing a network attacker with a CA-trusted certificate containing any IP SubjectAltName to intercept libgit2 connections to IP-literal HTTPS URLs. DNS SubjectAltName validation and non-OpenSSL TLS backends are not affected. This issue is fixed in versions 1.8.6 and 1.9.5.","modified":"2026-09-02T19:36:19.587208059Z","published":"2026-08-20T19:16:00Z","upstream":["CVE-2026-53583"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-53583"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-53583"},{"type":"REPORT","url":"https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp"}],"affected":[{"package":{"name":"libgit2","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.0-2","0.19.0-2ubuntu0.4","0.19.0-2ubuntu0.4+esm1","0.19.0-2ubuntu0.4+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"libgit2-0","binary_version":"0.19.0-2ubuntu0.4+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=esm-apps-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.22.2-2","0.23.1-1","0.24.1-2","0.24.1-2ubuntu0.2","0.24.1-2ubuntu0.2+esm1","0.24.1-2ubuntu0.2+esm2","0.24.1-2ubuntu0.2+esm3"],"ecosystem_specific":{"binaries":[{"binary_name":"libgit2-24","binary_version":"0.24.1-2ubuntu0.2+esm3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.25.1+really0.24.6-1","0.26.0+dfsg.1-1.1","0.26.0+dfsg.1-1.1build1","0.26.0+dfsg.1-1.1ubuntu0.2","0.26.0+dfsg.1-1.1ubuntu0.2+esm1","0.26.0+dfsg.1-1.1ubuntu0.2+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"libgit2-26","binary_version":"0.26.0+dfsg.1-1.1ubuntu0.2+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.27.7+dfsg.1-0.2build1","0.28.3+dfsg.1-1","0.28.3+dfsg.1-1ubuntu1","0.28.4+dfsg.1-2","0.28.4+dfsg.1-2ubuntu0.1","0.28.4+dfsg.1-2ubuntu0.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.28.4+dfsg.1-2ubuntu0.1+esm1","binary_name":"libgit2-28"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.0+dfsg.1-4","1.1.0+dfsg.1-4.1","1.1.0+dfsg.1-4.1build1","1.1.0+dfsg.1-4.1ubuntu0.1","1.1.0+dfsg.1-4.1ubuntu0.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libgit2-1.1","binary_version":"1.1.0+dfsg.1-4.1ubuntu0.1+esm1"},{"binary_version":"1.1.0+dfsg.1-4.1ubuntu0.1+esm1","binary_name":"libgit2-fixtures"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.1+ds-1ubuntu1","1.7.1+ds-2ubuntu1","1.7.2+ds-1ubuntu1","1.7.2+ds-1ubuntu2","1.7.2+ds-1ubuntu3","1.7.2+ds-1ubuntu3.1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.7.2+ds-1ubuntu3.1","binary_name":"libgit2-1.7"},{"binary_name":"libgit2-fixtures","binary_version":"1.7.2+ds-1ubuntu3.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.9.0+ds-2ubuntu2","1.9.1+ds-1ubuntu1","1.9.1+ds-1ubuntu1.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libgit2-1.9","binary_version":"1.9.1+ds-1ubuntu1.1"},{"binary_name":"libgit2-fixtures","binary_version":"1.9.1+ds-1ubuntu1.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}