{"id":"CVE-2026-53587","aliases":["GHSA-pm24-4jhq-3xvm"],"url":"https://o3.security/vulnerability/CVE-2026-53587","summary":"libgit2 - Unauthenticated network-reachable heap out-of-bounds read in transports/smart_pkt.c:set_data","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.","published":"2026-08-20T18:36:43.055Z","modified":"2026-08-22T03:58:06.527404091Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/libgit2/libgit2/commit/2c0ce8c0132ac38ab0db28239462a671e2e5440e","label":"libgit2/libgit2@2c0ce8c"},"references":[{"type":"WEB","url":"https://github.com/libgit2/libgit2/releases/tag/v1.8.6"},{"type":"WEB","url":"https://github.com/libgit2/libgit2/releases/tag/v1.9.5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53587.json"},{"type":"ADVISORY","url":"https://github.com/libgit2/libgit2/security/advisories/GHSA-pm24-4jhq-3xvm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53587"},{"type":"FIX","url":"https://github.com/libgit2/libgit2/commit/2c0ce8c0132ac38ab0db28239462a671e2e5440e"},{"type":"FIX","url":"https://github.com/libgit2/libgit2/commit/affda60c10fcef16723451c0d7dc71b71dc20ad3"},{"type":"FIX","url":"https://github.com/libgit2/libgit2/commit/d7a9fb87f504434e9f45228678953c4fa56e7640"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-22T03:58:06.527404091Z"}}