CVE-2026-53586 libgit2: HTTP transport can leak credentials to an offsite redirect target
libgit2 leaks HTTP Basic credentials to offsite redirect targets, allowing attackers to steal user credentials via open redirects.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-53586?
CVE-2026-53586 is a medium-severity vulnerability in libgit2, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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->owner->url instead of transport->server.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->server.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.
Which versions are affected by CVE-2026-53586?
How do I fix CVE-2026-53586?
Upgrade to a fixed version.
Is CVE-2026-53586 being exploited?
There is no known exploitation of CVE-2026-53586 in the wild and no public exploit code.
Sources
Also known as AZL-96962, BELL-CVE-2026-53586, DEBIAN-CVE-2026-53586, ECHO-6732-0e6e-c6bd, GHSA-2889-x8f6-mc4x, JLSEC-2026-1372 and 3 more.