The vulnerability is a path‑traversal flaw in the /api/chats/import endpoint of SillyTavern. By injecting directory traversal sequences into the character_name field, an authenticated user can cause the application to write files outside the designated chats directory. This allows the attacker to create or overwrite arbitrary files on the system, potentially enabling code execution, data exfiltration, or other abuses. The weakness is classified as CWE‑22 and CWE‑73, resulting in an arbitrary file write that compromises integrity and confidentiality of the host environment.

Affected systems are SillyTavern installations in all versions earlier than 1.17.0. Users who run the locally installed application and authenticate to the API before the 1.17.0 release are vulnerable. The problem was fixed in release 1.17.0.

The CVSS score of 8.1 indicates high severity, but the EPSS score is below 1%, suggesting a low current exploitation probability. Because the flaw requires an authenticated session, the actual risk is limited to users who can log in to the local interface or have local access to the server. The vulnerability is not listed in the CISA KEV catalog, so there are no known exploits yet, but the high severity warrants prompt action.