Horizon Alert
Summary of the vulnerability and why it matters
This advisory concerns a critical vulnerability in Gitea Actions Artifacts that could allow unauthorized access to sensitive information or unauthorized modifications to application states. The vulnerability arises from an ambiguity in how signed URLs are handled, potentially impacting the integrity and confidentiality of artifacts shared between repositories. The main concern is confirming relevance and exposure within your Gitea deployments.
- Ambiguity allows unauthorized reading and writing.
- Critical access risk if Gitea is deployed externally.
- Confirm Gitea deployment relevance and exposure.
Attack Path
How an attacker could exploit the issue
An attacker with limited access to a Gitea instance could potentially read artifacts from any repository and modify upload states in other tasks. This is possible due to a weakness in how signed URLs for Gitea Actions artifacts are processed, specifically an HMAC ambiguity. Successful exploitation could allow an attacker to access sensitive information or disrupt ongoing operations.
- Requires authenticated access to Gitea.
- Exploits HMAC ambiguity in signed URLs.
- Leads to cross-repository data access and modification.
Live Threat
Current exploitation, exposure, and threat context
When supported by the advisory, this vulnerability could allow a low-privileged attacker to read artifacts from other repositories and potentially write to upload states of other tasks within Gitea Actions.
- Cross-repository artifact data.
- Authenticated user actions.
- Unauthorized data access and modification.
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability in Gitea Actions Artifacts affects repositories and tasks, indicating that platform or application teams managing Gitea instances are likely responsible. The immediate priority is to identify all Gitea deployments, determine their exposure, and confirm ownership to plan remediation.
- Platform/Application teams own remediation.
- Verify Gitea instance exposure and criticality.
- Coordinate vendor update or planned upgrade.
