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gix and gitoxide: unvalidated submodule name traverses out of .git/modules and redirects state() / open() to another repository

High severity GitHub Reviewed Published Apr 25, 2026 in GitoxideLabs/gitoxide • Updated May 5, 2026

Package

cargo gitoxide (Rust)

Affected versions

<= 0.52.0

Patched versions

0.52.1
cargo gix (Rust)
< 0.83.0
0.83.0

Description

Summary

attachments:
pocs.zip

Submodule names coming from .gitmodules are exposed as unvalidated names and are later reused to derive the submodule git directory as:

<superproject common_dir>/modules/<submodule name>

Because the submodule name is joined directly as a filesystem path component, a name such as ../../../escaped-target.git escapes .git/modules after normalization. The current implementation then uses that escaped path in both state() and open().

The updated PoC demonstrates the real sink, not just string construction:

  • state() reports repository_exists=true for the traversed path;
  • open() returns a repository whose normalized common_dir() matches the attacker-chosen repository outside .git/modules.

Root cause analysis

The relevant flow is:

  1. gix-submodule/src/access.rs exposes unvalidated submodule names from configuration.
  2. gix/src/submodule/mod.rs derives the git directory by doing common_dir().join("modules").join(name) with no confinement check.
  3. gix/src/submodule/mod.rs uses that derived path during state resolution and repository opening.

There is no normalization-and-confinement step between “submodule name from configuration” and “filesystem path used for repository existence checks / open.” As a result, traversal segments in the submodule name directly influence which repository path is inspected and opened.

Reproduce steps

Use the attached PoC zip that contains the pocs/ workspace.

  1. Unzip the PoC archive.

  2. Enter pocs/F002.

  3. Run:

    cargo run --quiet

  4. Compare the output with pocs/F002/result.txt.

Key outputs are:

  • submodule_name=../../../escaped-target.git
  • derived_git_dir_raw=.../.git/modules/../../../escaped-target.git
  • derived_git_dir_normalized=.../artifacts/escaped-target.git
  • escaped_target=.../artifacts/escaped-target.git
  • repository_exists=true
  • submodule_opened=true
  • opened_common_dir_normalized=.../artifacts/escaped-target.git
  • normalized_git_dir_matches_target=true
  • opened_common_dir_matches_target=true
  • target_outside_modules_root=true

These outputs show that gitoxide is not only constructing a traversable path string. It is actually using the escaped path for repository existence checks and for opening a repository object.

Impact

Confirmed impact:

  • a malicious submodule name can redirect submodule state inspection away from .git/modules/<name> to an attacker-chosen repository path outside .git/modules;
  • Submodule::state() can report repository existence for the wrong repository;
  • Submodule::open() can return a repository object backed by that attacker-chosen path.

This is best described as a path-traversal / repository-confusion issue in submodule repository resolution.

This report does not claim command execution from this behavior alone. The demonstrated impact is repository redirection: callers that enumerate, inspect, or operate on submodules can be steered into using the wrong repository.

Recommended fix

Two complementary fixes are advisable:

  1. do not reuse raw submodule names as filesystem path fragments;
    • either use a validated/sanitized name for filesystem derivation,
    • or derive the storage path from a safe identifier instead of the user-controlled name;
  2. add an explicit confinement check after path derivation;
    • normalize or canonicalize the candidate path,
    • verify that the result stays under <common_dir>/modules,
    • reject names that contain traversal segments, path separators, or any representation that can escape the modules root.

In short, submodule names may remain opaque configuration identifiers, but they should not be treated as trusted filesystem subpaths.

References

@Byron Byron published to GitoxideLabs/gitoxide Apr 25, 2026
Published to the GitHub Advisory Database May 5, 2026
Reviewed May 5, 2026
Last updated May 5, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity None
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P

EPSS score

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Learn more on MITRE.

CVE ID

No known CVE

GHSA ID

GHSA-fr8x-3vfx-f45h

Source code

Credits

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