CVE-2026-44649 PUBLISHED

SillyTavern: Authentication Bypass via SSO Header Injection

Assigner: GitHub_M
Reserved: 07.05.2026 Published: 29.05.2026 Updated: 29.05.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 9.8

Product Status

Vendor SillyTavern
Product SillyTavern
Versions
  • Version < 1.18.0 is affected

References

Problem Types

  • CWE-290: Authentication Bypass by Spoofing CWE
  • CWE-306: Missing Authentication for Critical Function CWE
  • CWE-346: Origin Validation Error CWE
  • CWE-807: Reliance on Untrusted Inputs in a Security Decision CWE