The vulnerability resides in SillyTavern’s POST /api/extensions/delete endpoint, where the server accepts an extensionName parameter without adequate validation. Supplying the value "." bypasses the sanitize‑filename routine, causing a recursive deletion of the entire user extensions directory. This results in loss of all installed extensions and any configuration or script data they contain, directly compromising the integrity and confidentiality of the user’s environment.

SillyTavern SillyTavern – any release prior to version 1.18.0. The fix is included in 1.18.0 and later versions.

The flaw carries a CVSS score of 9.1, marking it a critical vulnerability. No EPSS score is available, and it is not listed in the CISA KEV catalog. Exploitation only requires an unauthenticated POST request to the vulnerable endpoint. In the default configuration the API is reachable locally, so a local attacker can trigger the deletion with ease. If the API is exposed externally, a remote attacker could also exploit it. The vulnerability was addressed in SillyTavern 1.18.0; any earlier installation remains at risk.