Lektor through 3.3.14 and 3.4.0b15 includes an absolute path traversal bug in the Windows‑only admin API. The flaw allows an attacker to supply drive‑letter paths that the cleanup_path function does not normalise, enabling escape from the intended project directory. By using malicious web pages that trigger cross‑site requests or DNS rebinding attacks on the unauthenticated local server, an adversary can delete directories recursively with the deleterecord call or create attacker‑controlled files via newattachment, leading to data loss or arbitrary code execution within the project scope.

The vulnerability affects deployments of the Lektor content‑management system, specifically versions 3.3.14 and the pre‑release 3.4.0b15. The issue is confined to Windows environments where the admin API is exposed. Users running these versions on local machines or internal networks are at risk, while the problem does not exist on non‑Windows operating systems.

The CVSS score of 5.9 places the flaw in the moderate range; however, the EPSS score is not available, and it is not listed in the CISA KEV catalog. Attacker access requires the ability to reach the unauthenticated local server and trigger the admin API via cross‑origin or DNS rebinding techniques. Because the flaw relies on specific Windows path handling, exploitation is limited to Windows hosts running the vulnerable Lektor versions. Despite the moderate severity, the ability to delete or overwrite project files can have significant impact on integrity and availability if the API is unrestrained.