Plex Media Server contains a server-side request forgery (SSRF) vulnerability which could allow an attacker using any X-Plex-Token value to include a full URL in the 'protocol' parameter and force the Plex server to POST to the attacker's chosen destination. This vulnerability can be chained with CVE-2026-96654, CVE-2026-96655, and CVE-2026-96656.
Required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA KEV status
This vulnerability is listed in CISA’s Known Exploited Vulnerabilities Catalog. Known ransomware campaign use: Unknown.