Executive brief
Weblate, a web-based translation platform, contains a vulnerability in its component creation feature. Authorized users can provide a malicious URL that forces the server to make requests to internal systems or local files. This could allow an attacker to steal sensitive information from internal services or cloud metadata endpoints, potentially leading to a full environment compromise.
Technical details
A Server-Side Request Forgery (SSRF) vulnerability exists in Weblate's 'Create Component' functionality due to insufficient validation of the repository URL field. When the Mercurial VCS backend is selected, an authenticated attacker can provide URLs using arbitrary protocols (such as file:// or http://) to probe internal network services or enumerate local files. Unlike the Git backend, the Mercurial implementation exposes the full server-side HTTP response or detailed error messages in the UI, allowing for data exfiltration or filesystem layout discovery. In cloud environments, this can be used to access IMDS endpoints for credential theft. The issue is fixed in version 5.15; a workaround involves disabling the Mercurial backend in configuration.
Affected products
- WeblateOrg Weblate < 5.15
Timeline
- 2025-12-15: disclosed: Initial disclosure to WeblateOrg
- 2025-12-16: advisory: NVD publication date
- 2026-05-26: advisory: GitHub Advisory published/updated