CVE-2026-31804: Tautulli: Unauthenticated pms_image_proxy endpoint proxies arbitrary HTTP requests through the Plex Media Server

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-03-30 · updated 2026-06-17
Weakness: CWE-918

Description

Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the /pms_image_proxy endpoint accepts a user-supplied img parameter and forwards it to Plex Media Server's /photo/:/ transcode transcoder without authentication and without restricting the scheme or host. The endpoint is intentionally excluded from all authentication checks in webstart.py, any value of img beginning with http is passed directly to Plex, this causes the Plex Media Server process, which typically runs on the same host or internal network as Tautulli, with access to RFC-1918 address space, to issue an outbound HTTP request to any attacker-specified URL. This issue has been patched in version 2.17.0.

Affected products

Tautulli: before 2.17.0 — fixed in 2.17.0

How to fix

Upgrade to a fixed version: Tautulli 2.17.0. Check the vendor advisory for mitigations.

References

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