{"id":"JLSEC-2026-1372","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":"2026-08-21T21:30:03.262865932Z","published":"2026-08-21T21:14:18.508Z","upstream":["CVE-2026-53586","EUVD-2026-63550"],"database_specific":{"license":"CC-BY-4.0","sources":[{"modified":"2026-08-20T19:16:54.983Z","published":"2026-08-20T19:16:54.983Z","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-53586","html_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53586","database_specific":{"status":"Received"},"id":"CVE-2026-53586","imported":"2026-08-21T20:45:35.145Z"},{"html_url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-63550","affected":{"libgit2:libgit2":["1.9.0, \u003c 1.9.5","\u003c 1.8.6"]},"id":"EUVD-2026-63550","imported":"2026-08-21T20:45:01.753Z","modified":"2026-08-20T18:40:08Z","published":"2026-08-20T18:40:08Z","url":"https://euvdservices.enisa.europa.eu/api/enisaid?id=EUVD-2026-63550"}]},"references":[{"type":"WEB","url":"https://github.com/libgit2/libgit2/commit/07de6a7e438f95ac9a6efd3222a82117e871ed27"},{"type":"WEB","url":"https://github.com/libgit2/libgit2/commit/af2b29ad0a74d5bac9751376879ddaf848136d3b"},{"type":"WEB","url":"https://github.com/libgit2/libgit2/commit/c1507abc44647b3acd832a33a5b1c8c9f5ba8821"},{"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":"WEB","url":"https://github.com/libgit2/libgit2/security/advisories/GHSA-2889-x8f6-mc4x"}],"affected":[{"package":{"name":"LibGit2_jll","ecosystem":"Julia","purl":"pkg:julia/LibGit2_jll?uuid=e37daf67-58a4-590a-8e99-b0245dd2ffc5"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.9.6+0"}]}],"database_specific":{"source":"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-1372.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","source":"CNA"}]}