The vulnerability resides in gpt-crawler versions up through 1.5.1. The software fails to validate the outputFileName field in the POST /crawl HTTP request, allowing anyone to write arbitrary files to the file system. An attacker can supply absolute paths or use parent‑directory references, overwriting existing files or creating new ones with content from attacker‑controlled sources. The weakness is an arbitrary file write, mapped to CWE‑22. This capability could enable attackers to replace executable files, modify configuration, or insert malicious scripts, compromising confidentiality, integrity, and availability of the system.

The affected product is BuilderIO’s gpt‑crawler, a web‑crawler tool. Versions up to and including 1.5.1 are vulnerable. No other versions or additional vendors are listed.

The CVSS score of 8.8 indicates high severity. The EPSS score is not available, and the vulnerability has not yet been listed in the CISA KEV catalog. The exploit can be performed without authentication by sending an HTTP POST to the /crawl endpoint and providing a crafted outputFileName value. Attackers can choose absolute paths or traverse directories to override critical files. Given the lack of authentication and the ability to write any path, the risk is significant, especially in exposed deployments.