CVE-2026-96656

Plex Media Server arbitrary file write

HIGH

7.2

CVSS Score

Published: September 23, 2026 at 04:07 PM UTC

Updated: October 21, 2026 at 01:09 PM UTC

1 product affected across 1 vendorMedia Server

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Severity

HIGH7.2

Exploitation

CISA KEV

Exploit prediction

EPSS 2%

SSVC

No known exploit

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score1.8%

EPSS (Exploit Prediction Scoring System) estimates a 1.8% chance this CVE is exploited in the wild within the next 30 days — higher than 78% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

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.

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.

Ransomware Use

Unknown

Added to KEV

Oct 20, 2026

Remediation Due

Oct 23, 2026

11 days overdue

Notes

https://forums.plex.tv/t/important-security-update-for-plex-media-server-v1-43-2-and-earlier/942319

BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk

Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk

https://nvd.nist.gov/vuln/detail/CVE-2026-96656

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.