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NVD / CVE Program· CNA GitHub_M

CVE-2026-53586: libgit2: HTTP transport can leak credentials to an offsite redirect target

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.27% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: 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.

Low priority for now. Upgrade to 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 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Aug 20, 2026
Updated
Oct 26, 2026
EPSS
0.2% · 20th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
6.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • libgit2 libgit2

    • < 1.8.6, >= 1.9.0, < 1.9.5affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12libgit2before 1.5.1+ds-1+deb12u21.5.1+ds-1+deb12u2
Debian:13libgit2before 1.9.0+ds-2+deb13u11.9.0+ds-2+deb13u1
Debian:14libgit2before 1.9.6+ds-11.9.6+ds-1
openSUSE:Tumbleweedlibgit2before 1.9.6-1.11.9.6-1.1
Red Hat:hummingbird:1libgit2before 0:1.9.7-1.hum10:1.9.7-1.hum1
Red Hat:hummingbird:1libgit2-develbefore 0:1.9.7-1.hum10:1.9.7-1.hum1

Same product

libgit2: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-12279An issue was discovered in libgit2 before 0.28.4 and 0.9x before 0.99.0.
    41Plan
  • CVE-2020-12278An issue was discovered in libgit2 before 0.28.4 and 0.9x before 0.99.0.
    41Plan
  • CVE-2024-24577libgit2 is vulnerable to arbitrary code execution due to heap corruption in `git_index_add`
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-53584Aug 20, 2026 · libgit2: Submodule path traversal
    17Monitor
  • ← EarlierCVE-2026-53585Aug 20, 2026 · libgit2: Unbounded Memory Allocation via Delta Object Result-Size Header
    21Monitor
  • Later →CVE-2026-53587Aug 20, 2026 · libgit2 - Unauthenticated network-reachable heap out-of-bounds read in transports/smart_pkt.c:set_data
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:libgit21.5.1+ds-1+deb12u2 · Debian:12Package registry (OSV)
debian:libgit21.9.0+ds-2+deb13u1 · Debian:13Package registry (OSV)
opensuse:libgit21.9.6-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:libgit20:1.9.7-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libgit2-devel0:1.9.7-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor

CVSS vector

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

nvd-secondary

Root cause

The extension requests broader permissions than its function needs and sends the data it collects out for purposes beyond its stated function.

The bug in code

The whole CWE-200 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

json
{  "permissions": ["tabs", "<all_urls>"],  "background": { "service_worker": "analytics.js" }}

Fixed

json
{  "permissions": ["activeTab"],  "host_permissions": ["https://yildiz.example/*"]}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records