Plex · Media Server
CVE-2026-96656
Plex Media Server arbitrary file write
What it is
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.
What to do
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.
Deadline for US federal agencies: October 23, 2026
More exploited flaws from Plex
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Oct 20, 2026 | Server-Side Request Forgery (SSRF) | Media Server | Medium 5.3 | 1.8% |
| Oct 20, 2026 | Improper Neutralization of Encoded URI Schemes in a Web Page | Media Server | Medium 6.9 | 1.9% |
| Oct 20, 2026 | Server-Side Request Forgery (SSRF) | Media Server | Medium 5.3 | 1.6% |
| Mar 10, 2023 | Remote Code Execution | Media Server | High 7.2 | 73% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.