Plex Media Server SSRF exploited in the wild (CVE-2026-96655)

Actively exploited in the wild - CVE-2026-96655 is a medium-severity server-side request forgery (SSRF) in Plex Media Server before 1.43.3.10861 that lets any authenticated user make the server send requests to arbitrary internal or external addresses. Patched in 1.43.3.10861 - update immediately.

Overview

The /video/:/transcode/universal endpoint accepts a path parameter that Plex Media Server uses to fetch media for transcoding. In versions before 1.43.3.10861, the server does not properly constrain where that parameter can point. An authenticated user can supply a crafted value and cause the server to issue requests to any address reachable from the Plex host, including loopback, private RFC 1918 ranges, link-local metadata endpoints, and the public internet.

In plain terms: whoever holds a Plex account on the server can use the server as a proxy. They do not need administrator rights, and they do not need any interaction from other users.

Impact

SSRF is a pivoting primitive. From the attacker’s point of view, the Plex process becomes a trusted client sitting behind the perimeter firewall. Typical consequences include:

• Probing internal networks and services that are not exposed externally.
• Reaching cloud instance metadata endpoints to retrieve credentials or configuration.
• Interacting with internal admin panels or APIs that trust requests originating from the LAN.
• Using the server’s egress to reach external addresses, which can mask the attacker’s origin.

The CVSS score is 5.3 (network, low complexity, low privileges, no user interaction), which reflects that authentication is required and that the attacker sees responses only indirectly. The real-world severity depends heavily on what sits on the same network segment as the Plex host. CISA has added this CVE to its Known Exploited Vulnerabilities catalog, confirming that attackers are using it, not just researching it.

Remediation and Mitigation

Update to Plex Media Server 1.43.3.10861 or later. This is the definitive fix and should be treated as the priority action.

If you cannot patch immediately:

• Restrict access to the Plex web and API interfaces to trusted networks only.
• Review Plex account sharing; remove users who no longer need access, since exploitation requires only a valid low-privilege account.
• Run Plex in a segmented network so that the host has no route to management interfaces or cloud metadata services.
• Audit Plex logs for requests where the transcode path parameter references unexpected hosts or private IP ranges.

Check whether your instance was probed; if you find evidence of unauthorized access, incident response should include a review of internal services the Plex host could reach.

Data breach reports are available at breach reports and cybersecurity news at security news.

Security Insight

Media servers are quietly becoming the soft target of choice because they combine internet exposure, large user bases with shared accounts, and endpoints built for flexibility rather than input validation. SSRF in a transcoding path is a textbook case: the feature exists to fetch remote content, so the code is already primed to make outbound requests. The KEV listing is the notable signal here. Plex deployments are overwhelmingly consumer and small-business installs where patching lags, giving attackers a durable pool of reachable hosts, and this CVE should be read as confirmation that SSRF in media platforms is now actively hunted rather than merely theoretical.

Further Reading

• All Medium Vulnerabilities
• Recent Critical Vulnerabilities
• Top Critical CVEs