libgit2: HTTP transport can leak credentials to an offsite redirect target

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-53586
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-20 19:16:54 UTC
Updated2026-08-20 19:16:54 UTC
Descriptionlibgit2 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Problem Types: CWE-200 | CWE-522 | CWE-601 | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor | CWE-522 CWE-522: Insufficiently Protected Credentials | CWE-601 CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Libgit2 Libgit2 affected < 1.8.6 Not specified
CNA Libgit2 Libgit2 affected >= 1.9.0, < 1.9.5 Not specified

References

ReferenceSourceLinkTags
github.com/libgit2/libgit2/releases/tag/v1.8.6 [email protected] github.com
github.com/libgit2/libgit2/commit/c1507abc44647b3acd832a33a5b1c8c9f5ba8821 [email protected] github.com
github.com/libgit2/libgit2/commit/07de6a7e438f95ac9a6efd3222a82117e871ed27 [email protected] github.com
github.com/libgit2/libgit2/commit/af2b29ad0a74d5bac9751376879ddaf848136d3b [email protected] github.com
github.com/libgit2/libgit2/security/advisories/GHSA-2889-x8f6-mc4x [email protected] github.com
github.com/libgit2/libgit2/releases/tag/v1.9.5 [email protected] github.com
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