libgit2 up to 1.8.5/1.9.4 HTTP Transport http.c handle_remote_auth/handle_auth information disclosure

Summaryinfo

A vulnerability categorized as problematic has been discovered in libgit2 up to 1.8.5/1.9.4. This impacts the function handle_remote_auth/handle_auth of the file src/libgit2/transports/http.c of the component HTTP Transport. Such manipulation leads to information disclosure. This vulnerability is uniquely identified as CVE-2026-53586. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in libgit2 up to 1.8.5/1.9.4. Affected by this issue is the function handle_remote_auth/handle_auth of the file src/libgit2/transports/http.c of the component HTTP Transport. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-53586 since 06/09/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1592 by the MITRE ATT&CK project.

Upgrading to version 1.8.6 or 1.9.5 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• libgit2

Version

• 1.8.0
• 1.8.1
• 1.8.2
• 1.8.3
• 1.8.4
• 1.8.5
• 1.9.0
• 1.9.1
• 1.9.2
• 1.9.3
• 1.9.4

Website

• Product: https://github.com/libgit2/libgit2/

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