CVEvulnerability

CVE-2026-96656

8.6 HIGH Known exploited Published 2026-09-23 Modified 2026-10-21 Official page ↗

CISA Known Exploited Vulnerability

Plex Media Server External Control of File Name or Path Vulnerability — Plex Media Server

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.

Added to KEV: 2026-10-20
Remediation due: 2026-10-23
Ransomware use: Unknown
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.
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

Status: Analyzed
Published: 2026-09-23
Last modified: 2026-10-21
Assigner: 9119a7d8-5eab-497f-8521-727c672e3725
CVSS 4.0 (9119a7d8-5eab-497f-8521-727c672e3725): 8.6 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 (9119a7d8-5eab-497f-8521-727c672e3725): 7.2 HIGH — CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Weaknesses: CWE-73

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.

Affected configurations

• plex media server (< 1.43.3.10861)

Weakness · CWE (1)

CWE-73 External Control of File Name or Path weakness

References