SillyTavern up to 1.17.x User Interface authentication spoofing

Summaryinfo

A vulnerability, which was classified as critical, was found in SillyTavern up to 1.17.x. Affected by this vulnerability is an unknown functionality of the component User Interface. Such manipulation leads to authentication spoofing. This vulnerability is traded as CVE-2026-44649. The attack may be launched remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in SillyTavern up to 1.17.x. It has been rated as critical. Affected by this issue is some unknown functionality of the component User Interface. The manipulation with an unknown input leads to a authentication spoofing vulnerability. Using CWE to declare the problem leads to CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. Impacted is confidentiality, integrity, and availability. CVE summarizes:

SillyTavern is a locally installed user interface that allows users to interact with text generation large language models, image generation engines, and text-to-speech voice models. Prior to 1.18.0, SillyTavern accepts Remote-User (Authelia) and X-Authentik-Username (Authentik) HTTP headers to automatically log in users when SSO is configured. There is no validation that these headers originate from a trusted reverse proxy. Any network client that can reach the SillyTavern port directly can inject these headers and authenticate as any user, including administrators, without a password. This vulnerability is exploitable only when sso.autheliaAuth: true or sso.authentikAuth: true is set in config.yaml (both default to false). This vulnerability is fixed in 1.18.0.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-44649 since 05/07/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available.

Upgrading to version 1.18.0 eliminates this vulnerability.

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Productinfo

Name

• SillyTavern

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17

Website

• Product: https://github.com/SillyTavern/SillyTavern/

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