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[ CVE-2026-96656 · Published 23 Sep 2026 ]

Plex Media Server admin setting allows code execution

Exploited · CISA KEV CVSS 7.2 EPSS <1%No fix listed yet

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-10-20

[ Analyst view ]Is this a red alert for you?

Patch within days

CISA lists it as exploited, but it needs Plex admin rights first.

Red alert if
You run an unpatched Plex Media Server on a machine that also holds business data, and its admin account could be compromised.
Can wait if
You do not run Plex, or it runs on an isolated home or media network and you update it this week.
What it is
Plex Media Server before 1.43.3.10861 lets an admin user write files that are run when the server loads, because a transcoder setting is passed on verbatim and all .so files are loaded at startup without checks.
Impact
Someone with admin access to Plex can run code on the machine that hosts it. If an attacker has stolen a Plex admin login, this turns that login into control of the host, which is often a NAS or server on the internal network.

How an attack would work MITRE ATT&CK

  1. T1078 Valid AccountsThe attacker uses a Plex admin account, for example one with a reused or stolen password.
  2. T1574 Hijack Execution FlowA crafted library file is placed where Plex loads it at startup.
  3. T1059 Command and Scripting InterpreterCode runs on the host with the Plex service's rights.

What to do

  1. Update Plex Media Server to 1.43.3.10861 or later.
  2. Make sure the Plex admin account uses a unique password and two-step verification.
  3. Do not run Plex on servers that also hold business data, and keep it off networks with sensitive systems.
Written with AI from the sources on this page on 23 Oct 2026. Check the vendor's advisory before you act.

[ Description ]Official description

Plex Media Server before 1.43.3.10861 allows an admin user to write arbitrary files that may be executed on load. The preference TranscoderH264Options is appended verbatim to x264's option string on every transcode. At startup, all .so files are run without signature, execute bit, or symbol checks.

CISA: Plex Media Server contains an external control of file name or path vulnerability which can allow an admin user to write arbitrary files that may be executed on load. This vulnerability can be chained with CVE-2026-96652, CVE-2026-96654, and CVE-2026-96655.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 23 Oct 2026): 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.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References