CVE-2024-39931: Gogs File Deletion Vulnerability

CVE-2024-39931 Overview

CVE-2024-39931 is a critical vulnerability in Gogs, a self-hosted Git service written in Go. The flaw, present through version 0.13.0, allows authenticated attackers to delete internal files on the server hosting the Gogs instance. The issue is classified under CWE-552 (Files or Directories Accessible to External Parties). Successful exploitation can corrupt repository state, disrupt service availability, and enable follow-on attacks against the host. The vulnerability requires only low-privileged authenticated access and can be triggered over the network without user interaction.

Critical Impact

Authenticated attackers with low privileges can delete arbitrary internal files on the Gogs server, leading to data loss, repository corruption, and potential service compromise.

Affected Products

• Gogs versions through 0.13.0
• Self-hosted Gogs Git service deployments
• All platforms running vulnerable Gogs binaries (Linux, Windows, macOS)

Discovery Timeline

• 2024-07-04 - CVE-2024-39931 published to NVD
• 2025-04-10 - Last updated in NVD database

Technical Details for CVE-2024-39931

Vulnerability Analysis

The vulnerability resides in Gogs functionality that handles file operations within repositories. An authenticated user with low privileges can craft requests that cause the application to operate on files outside the intended repository scope. Because Gogs runs server-side file operations using the privileges of the Gogs process, deletions can affect internal files used by the application itself, not only repository content.

The issue is mapped to CWE-552, which covers files or directories that become accessible to external parties due to improper restriction of operations on resources. SonarSource researchers documented this and related issues in their analysis of unpatched Gogs vulnerabilities.

Because the attack vector is network-based and the scope is changed (the impact extends beyond the vulnerable component to the underlying host filesystem), the vulnerability carries significant risk for any organization exposing Gogs to untrusted or semi-trusted users.

Root Cause

The root cause is insufficient validation of file paths and operation targets in Gogs request handlers. The application does not adequately restrict deletion operations to authorized repository content, allowing references to internal files used by the Gogs service to be processed as valid targets.

Attack Vector

An attacker authenticates to a vulnerable Gogs instance using any low-privileged account, including accounts created through self-registration if enabled. The attacker then submits a request that triggers a file deletion routine, supplying input that resolves to an internal file path. The Gogs process performs the deletion using its own filesystem privileges. No user interaction is required.

The vulnerability manifests in the file handling logic for repository operations. See the SonarSource technical analysis for detailed exploitation mechanics.

Detection Methods for CVE-2024-39931

Indicators of Compromise

• Unexpected absence of internal Gogs files such as configuration, session data, or authentication tokens under the Gogs working directory
• Repository operations failing due to missing internal state files
• Anomalous DELETE or POST requests to Gogs API endpoints involving file or repository path parameters
• Authentication or session anomalies following file deletion events

Detection Strategies

• Monitor Gogs application logs for repeated or unusual file operation requests from a single authenticated user
• Enable filesystem auditing on the Gogs data directory using auditd on Linux to log deletions performed by the Gogs process
• Inspect web access logs for requests with suspicious path parameters or directory traversal patterns targeting Gogs endpoints

Monitoring Recommendations

• Correlate authentication events with subsequent file operation requests to identify low-privileged accounts performing destructive actions
• Alert on changes to files in the Gogs installation directory that occur outside scheduled maintenance windows
• Track creation of new low-privileged accounts followed by immediate API activity, which may indicate exploitation through self-registration

How to Mitigate CVE-2024-39931

Immediate Actions Required

• Upgrade Gogs to a patched release listed in the Gogs GitHub releases page
• Disable self-registration on Gogs instances exposed to untrusted networks to limit attacker access to authenticated endpoints
• Restrict network access to Gogs using firewall rules or a reverse proxy with authentication enforcement
• Audit existing user accounts and remove or disable accounts that are inactive or unverified

Patch Information

The Gogs project tracks fixes in its release notes on GitHub. Administrators should review release notes for versions after 0.13.0 and apply the latest stable build. Verify the running version with the Gogs admin panel or by checking the binary version output after upgrade.

Workarounds

• Place Gogs behind a reverse proxy that enforces additional authentication, such as mutual TLS or single sign-on
• Run the Gogs process under a dedicated low-privilege system account with filesystem permissions limited to required directories
• Restrict registration to administrator-approved invitations only, eliminating anonymous account creation
• Take regular backups of the Gogs data directory and repository storage to enable recovery from destructive actions

# Configuration example: disable self-registration in app.ini
[service]
DISABLE_REGISTRATION = true
REQUIRE_SIGNIN_VIEW = true
ENABLE_CAPTCHA = true