CVE-2026-43986: Tautulli vulnerable to unauthenticated SSRF in /image/<hash> via attacker-seeded image hash replay

Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Versions prior to 2.17.1 expose a public /image/<hash> route that resolves attacker-controlled entries from imagehashlookup and replays them through the same server-side image fetch logic used by authenticated image proxying. A low-privilege guest user can seed a malicious external image URL into this lookup table and then trigger server-side fetches through a fully unauthenticated endpoint. This turns an authenticated SSRF primitive into a persistent unauthenticated SSRF gadget. Once the malicious hash entry exists, any external user can request /image/<hash>.png and cause the PMS or Tautulli host to fetch an arbitrary attacker-chosen URL. Version 2.17.1 patches the issue.