The vulnerability in changedetection.io version 0.55.7 involves the Spec resource at /api/v1/full-spec, whose GET method lacks the @auth.check_token decorator and @validate_openapi_request validation. As a result, unauthenticated users can access the complete OpenAPI schema, exposing detailed API structure and registered plugins. This exposure occurs despite other sibling API routes enforcing API key authentication via the x-api-key header. The CVSS 3.1 base score is 5.3, reflecting a medium severity with network attack vector, low complexity, no privileges required, and no user interaction needed. No official patch or remediation level has been provided yet.

An unauthenticated attacker can retrieve the full OpenAPI schema of the changedetection.io API, revealing all endpoint paths, parameters, and registered processor plugins. This information disclosure could aid attackers in understanding the API's structure and potentially facilitate further attacks. However, no direct integrity or availability impact is indicated, and no known exploits are reported in the wild.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to the /api/v1/full-spec endpoint through network controls or API gateway rules to prevent unauthenticated access. Monitor vendor communications for an official fix or update.