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How CVE-2026-55228 Works
Weblate is a web-based continuous localization platform used to manage software translations. In versions prior to 2026.7, the REST API did not properly enforce the scope of project- and workspace-scoped teams, allowing a user to submit invalid team configurations through the API.
The core of the vulnerability lies in the `GroupViewSet` API endpoint, which is responsible for managing team configurations. Due to missing authorization checks, the API accepted requests that assigned projects to teams without verifying that the authenticated user had the necessary permissions for those projects.
An attacker with authenticated project manager-level access could craft a malicious API request, manipulating the project identifier in the team configuration payload. By assigning a private project they do not own to a team they control, they effectively grant themselves and other team members unauthorized read access to that project.
The root cause is an Insecure Direct Object Reference (IDOR) vulnerability, categorized under CWE-639: Authorization Bypass Through User-Controlled Key. The API relied on user-supplied input (the project key) without validating it against the user’s actual permissions.
This flaw allowed unauthorized access to private projects, exposing sensitive translation data, repository contents, and permitting project-management operations beyond the user’s intended scope. The vulnerability is remotely exploitable over the network, requires low privileges (authenticated project manager), and does not require user interaction.
The issue was independently reported by four security researchers and has been addressed in Weblate version 2026.7. Users are strongly advised to upgrade to this version or later to mitigate the risk.
DailyCVE Form
Platform: WeblateOrg/weblate
Version: < 2026.7
Vulnerability: IDOR in GroupViewSet
Severity: High (CVSS 8.1)
Date: August 26, 2026
Prediction: Already Patched (2026.7)
What Undercode Say
Check current Weblate version
weblate --version
Check if vulnerable endpoint is exposed
curl -X GET https://your-weblate-instance/api/groups/ -H "Authorization: Token YOUR_API_TOKEN"
Attempt to assign project to team (PoC concept)
curl -X POST https://your-weblate-instance/api/groups/ -H "Authorization: Token YOUR_API_TOKEN" -H "Content-Type: application/json" -d '{"name": "malicious-team", "projects": ["private-project-id"]}'
Analytics:
- CVSS Score: 8.1 (High)
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: Low
- User Interaction: None
- Confidentiality Impact: High
- Integrity Impact: High
- CWE: 639 – Authorization Bypass Through User-Controlled Key
- EPSS: Not yet available
Exploit (Educational Purposes!)
To exploit this vulnerability, an attacker with a valid API token and project manager permissions would:
1. Identify a target private project by its unique ID (e.g., via enumeration or guessing).
2. Craft a POST request to the `/api/groups/` endpoint, specifying the target project ID in the `projects` field of the JSON payload.
3. Submit the request with their authentication token.
Due to the missing validation on the server side, the API would accept the configuration and grant the attacker’s team unauthorized access to the private project. This would allow the attacker to view translations, access the repository, and perform management operations on the compromised project.
Protection
- Immediate: Upgrade Weblate to version 2026.7 or later.
- Workaround: If immediate upgrade is not possible, restrict API access to trusted IPs and monitor API logs for suspicious `GroupViewSet` activities.
- Long-term: Implement strict input validation and authorization checks on all API endpoints that handle user-controlled object references.
Impact
- Data Breach: Exposure of private project translations and sensitive content.
- Privilege Escalation: Unauthorized performance of translation, repository, and project-management operations.
- Reputation Damage: Loss of trust in the platform’s security posture.
- Compliance Violations: Potential breach of data protection regulations if sensitive data is exposed.
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Sources:
Reported By: github.com
Extra Source Hub:
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