{"id":"UBUNTU-CVE-2026-53586","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, the built-in HTTP transport in src/libgit2/transports/http.c follows an offsite initial redirect, and handle_remote_auth and handle_auth pass transport-\u003eowner-\u003eurl instead of transport-\u003eserver.url to the credential callback when the redirected host returns 401 Unauthorized. A callback that scopes credentials to the original trusted URL can therefore return GIT_CREDENTIAL_USERPASS_PLAINTEXT credentials that libgit2 stores in transport-\u003eserver.cred and sends as an Authorization header to the redirected host. An attacker who controls a trusted Git host or an open redirect on that host can disclose HTTP Basic credentials, personal access tokens, or equivalent credentials. This issue is fixed in versions 1.8.6 and 1.9.5.","modified":"2026-09-02T19:35:54.653674882Z","published":"2026-07-31T00:00:00Z","related":["USN-8628-1"],"upstream":["CVE-2026-53586"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-53586"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-53586"},{"type":"REPORT","url":"https://github.com/libgit2/libgit2/security/advisories/GHSA-2889-x8f6-mc4x"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8628-1"}],"affected":[{"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"},{"fixed":"0.28.4+dfsg.1-2ubuntu0.1+esm1"}]}],"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"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"libgit2-28","binary_version":"0.28.4+dfsg.1-2ubuntu0.1+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53586.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"},{"fixed":"1.1.0+dfsg.1-4.1ubuntu0.1+esm1"}]}],"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"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","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-2026-53586.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.7.2+ds-1ubuntu3.1"}]}],"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"],"ecosystem_specific":{"binaries":[{"binary_name":"libgit2-1.7","binary_version":"1.7.2+ds-1ubuntu3.1"},{"binary_name":"libgit2-fixtures","binary_version":"1.7.2+ds-1ubuntu3.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53586.json"}},{"package":{"name":"libgit2","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libgit2?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.1+ds-1ubuntu1.1"}]}],"versions":["1.9.0+ds-2ubuntu2","1.9.1+ds-1ubuntu1"],"ecosystem_specific":{"availability":"No subscription required","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-2026-53586.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N"},{"type":"Ubuntu","score":"medium"}]}