libgit2: HTTP transport can leak credentials to an offsite redirect target
libgit2 · libgit2
6.5MediumCVSS 3.1
Recommended action
Scheduled
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Patch available
Distribution package intelligence
Ubuntu vendor package status
Canonical’s release and source-package findings are shown separately from local repository availability.
1 package state
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
Ubuntu release
Source package
Vendor state
Fixed version
Evidence
Ubuntu 24.04 LTSnoble · standard archive
libgit2
Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
1 current
CVE-2026-53586 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitylibgit2: libgit2: Information disclosure via HTTP redirect allows credential leakage
37 known affected
The vendor explicitly identifies these products as affected by this CVE.
cargo as a component of Red Hat Enterprise Linux 10
clippy as a component of Red Hat Enterprise Linux 10
rust-analyzer as a component of Red Hat Enterprise Linux 10
rust-debugger-common as a component of Red Hat Enterprise Linux 10
rust-doc as a component of Red Hat Enterprise Linux 10
rust-gdb as a component of Red Hat Enterprise Linux 10
rust-lldb as a component of Red Hat Enterprise Linux 10
rust-src as a component of Red Hat Enterprise Linux 10
rust-std-static as a component of Red Hat Enterprise Linux 10
rust-std-static-aarch64-unknown-none-softfloat as a component of Red Hat Enterprise Linux 10
rust-std-static-wasm32-unknown-unknown as a component of Red Hat Enterprise Linux 10
rust-std-static-wasm32-wasip1 as a component of Red Hat Enterprise Linux 10
Summary
A flaw was found in libgit2. The built-in HTTP transport component incorrectly handles offsite redirects, leading to the disclosure of sensitive information. An attacker controlling a trusted Git host or an open redirect on that host could exploit this by causing the library to send HTTP Basic credentials or personal access tokens to an unintended third-party server. This vulnerability results in the leakage of user authentication credentials.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-63550
No EUVD known-exploited evidence
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.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
6.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Patch available
01
What, why and how
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.
What
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.
Why
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
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.
Why
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.None recorded
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
Likely attack path
a network path → Exposure of Sensitive Information to an Unauthorized Actor → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkUnauthenticatedCWE-200
A
Official authority intelligence
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2026-63550Official EUVD mapping
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.
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 20 Aug 2026 · Last source change 21 Aug 2026, 21:46 UTC · CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-23
European sourceENISA EUVD · EUVD-2026-63550
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD awaiting enrichment
Core structured fields are present and their contributing authorities are shown above.
Affected versionsThe structured affected or fixed version information changed.
Before
cargo as a component of Red Hat Enterprise Linux 10; clippy as a component of Red Hat Enterprise Linux 10; rust-analyzer as a component of Red Hat Enterprise Linux 10; rust-debugger-common as a component of Red Hat Enterprise Linux 10; rust-doc as a component of Red Hat Enterprise Linux 10; rust-gdb as a component of Red Hat Enterprise Linux 10; rust-lldb as a component of Red Hat Enterprise Linux 10; rust-src as a component of Red Hat Enterprise Linux 10; rust-std-static as a component of Red Hat Enterprise Linux 10; rust-std-static-aarch64-unknown-none-softfloat as a component of Red Hat Enterprise Linux 10; rust-std-static-wasm32-unknown-unknown as a component of Red Hat Enterprise Linux 10; rust-std-static-wasm32-wasip1 as a component of Red Hat Enterprise Linux 10; rust-std-static-x86_64-unknown-none as a component of Red Hat Enterprise Linux 10; rust-toolset as a component of Red Hat Enterprise Linux 10; rust-toolset-srpm-macros as a component of Red Hat Enterprise Linux 10; rust.src as a component of Red Hat Enterprise Linux 10; rustfmt as a component of Red Hat Enterprise Linux 10; libgit2-devel as a component of Red Hat Enterprise Linux 8; libgit2.src as a component of Red Hat Enterprise Linux 8; cargo as a component of Red Hat Enterprise Linux 9; clippy as a component of Red Hat Enterprise Linux 9; rust as a component of Red Hat Enterprise Linux 9; rust-analysis as a component of Red Hat Enterprise Linux 9; rust-analyzer as a component of Red Hat Enterprise Linux 9; rust-debugger-common as a component of Red Hat Enterprise Linux 9; rust-doc as a component of Red Hat Enterprise Linux 9; rust-gdb as a component of Red Hat Enterprise Linux 9; rust-lldb as a component of Red Hat Enterprise Linux 9; rust-src as a component of Red Hat Enterprise Linux 9; rust-std-static as a component of Red Hat Enterprise Linux 9; and 8 more
After
cargo as a component of Red Hat Enterprise Linux 10; clippy as a component of Red Hat Enterprise Linux 10; rust-analyzer as a component of Red Hat Enterprise Linux 10; rust-debugger-common as a component of Red Hat Enterprise Linux 10; rust-doc as a component of Red Hat Enterprise Linux 10; rust-gdb as a component of Red Hat Enterprise Linux 10; rust-lldb as a component of Red Hat Enterprise Linux 10; rust-src as a component of Red Hat Enterprise Linux 10; rust-std-static as a component of Red Hat Enterprise Linux 10; rust-std-static-aarch64-unknown-none-softfloat as a component of Red Hat Enterprise Linux 10; rust-std-static-wasm32-unknown-unknown as a component of Red Hat Enterprise Linux 10; rust-std-static-wasm32-wasip1 as a component of Red Hat Enterprise Linux 10; rust-std-static-x86_64-unknown-none as a component of Red Hat Enterprise Linux 10; rust-toolset as a component of Red Hat Enterprise Linux 10; rust-toolset-srpm-macros as a component of Red Hat Enterprise Linux 10; rust.src as a component of Red Hat Enterprise Linux 10; rustfmt as a component of Red Hat Enterprise Linux 10; libgit2-devel as a component of Red Hat Enterprise Linux 8; libgit2.src as a component of Red Hat Enterprise Linux 8; cargo as a component of Red Hat Enterprise Linux 9; clippy as a component of Red Hat Enterprise Linux 9; rust as a component of Red Hat Enterprise Linux 9; rust-analysis as a component of Red Hat Enterprise Linux 9; rust-analyzer as a component of Red Hat Enterprise Linux 9; rust-debugger-common as a component of Red Hat Enterprise Linux 9; rust-doc as a component of Red Hat Enterprise Linux 9; rust-gdb as a component of Red Hat Enterprise Linux 9; rust-lldb as a component of Red Hat Enterprise Linux 9; rust-src as a component of Red Hat Enterprise Linux 9; rust-std-static as a component of Red Hat Enterprise Linux 9; and 7 more · Fixed: libgit2-main@aarch64 as a component of Red Hat Hardened Images; libgit2-main@src as a component of Red Hat Hardened Images; libgit2-main@x86_64 as a component of Red Hat Hardened Images
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
CVE-2026-53586: libgit2: HTTP transport can leak credentials to an offsite redirect target | BlackTree
