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Fencer Intel
medium 6.5

CVE-2026-53586 json

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

published 2mo ago modified 14d ago also EUVD-2026-63550 , JLSEC-2026-1372

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • julia LibGit2_jll 1.9.6+0
  • libgit2 libgit2 1.8.6, 1.9.5
  • libgit2 Debian 12 1.5.1+ds-1+deb12u2
  • libgit2 Debian 13 1.9.0+ds-2+deb13u1
  • libgit2 Debian 14 1.9.6+ds-1

debian advisories DEBIAN-CVE-2026-53586

  • libgit2 Ubuntu 24.04 LTS 1.7.2+ds-1ubuntu3.1
  • libgit2 Ubuntu 26.04 LTS 1.9.1+ds-1ubuntu1.1
  • libgit2 Ubuntu Pro 20.04 LTS 0.28.4+dfsg.1-2ubuntu0.1+esm1
  • libgit2 Ubuntu Pro 22.04 LTS 1.1.0+dfsg.1-4.1ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2026-53586

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libgit2 hummingbird 1 1.9.7-1.hum1

red hat advisories RHSA-2026:59361

  • libgit2 openSUSE Tumbleweed 1.9.6-1.1

opensuse advisories openSUSE-SU-2026:11315-1

  • libgit2 Alpine 3.24, Alpine 3.23 1.9.6-r0

alpine advisories ALPINE-CVE-2026-53586

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libgit2 Azure Linux 3.0 1.7.2-3

azure linux advisories AZL-96962

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-53586 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-53586 updated cvss 6.5

libgit2: libgit2: Information disclosure via HTTP redirect allows credential leakage

  • Red Hat Enterprise Linux 8 libgit2 Red Hat Enterprise Linux 9 rust, cargo, clippy, rustfmt, rust-gdb, rust-src, +8 more Red Hat Enterprise Linux 10 rust Red Hat Enterprise Linux AI (RHEL AI) 3 rust, libgit2
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images libgit2 1.9.7-1.hum1
    fixed: vendor fix RHSA-2026:59361

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
julia LibGit2_jll
<1.9.6+0
1.9.6+0

Affected products

  • libgit2 libgit2

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-522 Insufficiently Protected Credentials
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.