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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-gxx6-h3g6-vwjh SillyTavern has Authentication Bypass via SSO Header Injection
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 29 May 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Sillytavern
Sillytavern sillytavern
Vendors & Products Sillytavern
Sillytavern sillytavern

Fri, 29 May 2026 18:30:00 +0000

Type Values Removed Values Added
Description 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.
Title SillyTavern: Authentication Bypass via SSO Header Injection
Weaknesses CWE-290
CWE-306
CWE-346
CWE-807
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-29T17:45:26.073Z

Reserved: 2026-05-07T15:30:10.875Z

Link: CVE-2026-44649

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-05-29T19:16:24.720

Modified: 2026-05-29T20:17:38.110

Link: CVE-2026-44649

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-29T19:30:05Z