{"id":"UBUNTU-CVE-2026-53587","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, libgit2 performs a fixed-size strncmp in set_data in src/libgit2/transports/smart_pkt.c without first verifying that the smart-protocol pkt-line capability buffer contains 14 bytes. A malicious Git server can make bytes after the pkt-line complete object-format=, causing format_str to advance beyond the pkt-line and the following memchr length calculation to underflow. The resulting heap out-of-bounds walk can crash a client during the first refs-advertisement packet over HTTP, HTTPS, SSH, or the Git protocol. This issue is fixed in versions 1.8.6 and 1.9.5.","modified":"2026-09-02T19:35:54.110744283Z","published":"2026-07-31T00:00:00Z","related":["USN-8628-1"],"upstream":["CVE-2026-53587"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-53587"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-53587"},{"type":"REPORT","url":"https://github.com/libgit2/libgit2/security/advisories/GHSA-pm24-4jhq-3xvm"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8628-1"}],"affected":[{"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":{"availability":"No subscription required","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-2026-53587.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":{"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"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53587.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:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}