Plex Media Server arbitrary file write

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-96656
StatePUBLISHED
Assignercisa-cg
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-23 17:17:23 UTC
Updated2026-10-21 13:09:18 UTC
DescriptionPlex 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.

Risk And Classification

Primary CVSS: v4.0 8.6 HIGH from 9119a7d8-5eab-497f-8521-727c672e3725

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

EPSS: 0.017850000 probability, percentile 0.783840000 (date 2026-11-05)

CISA KEV: Listed on 2026-10-20; due 2026-10-23; ransomware use Unknown

Problem Types: CWE-73 | CWE-73 CWE-73 External Control of File Name or Path

VersionSourceTypeScoreSeverityVector
4.09119a7d8-5eab-497f-8521-727c672e3725Secondary8.6HIGHCVSS: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/C...
4.0CNADECLARED8.6HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
3.19119a7d8-5eab-497f-8521-727c672e3725Secondary7.2HIGHCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.2HIGHCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
High
User Interaction
None
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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 v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CISA Known Exploited Vulnerability

VendorPlex
ProductMedia Server
NamePlex Media Server External Control of File Name or Path Vulnerability
Required ActionApply 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.
Noteshttps://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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Plex Media Server All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Plex Media Server affected 1.43.3.10861 custom Not specified
CNA Plex Media Server unaffected 1.43.3.10861 Not specified

References

ReferenceSourceLinkTags
www.cve.org/CVERecord 9119a7d8-5eab-497f-8521-727c672e3725 www.cve.org Third Party Advisory, VDB Entry
zmain.info/blog/plex2shell 9119a7d8-5eab-497f-8521-727c672e3725 zmain.info Third Party Advisory
forums.plex.tv/t/plex-media-server/30447/711 9119a7d8-5eab-497f-8521-727c672e3725 forums.plex.tv Release Notes
www.cisa.gov/known-exploited-vulnerabilities-catalog 134c704f-9b21-4f2e-91b3-4a467353bcc0 www.cisa.gov US Government Resource
raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-266-01.json 9119a7d8-5eab-497f-8521-727c672e3725 raw.githubusercontent.com Third Party Advisory
www.boredhackerblog.info/2026/10/plex-vulnerabilities-being-exploited-in.html 134c704f-9b21-4f2e-91b3-4a467353bcc0 www.boredhackerblog.info Third Party Advisory
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
CISA Known Exploited Vulnerabilities catalog CISA www.cisa.gov kev

Vendor Comments And Credit

Discovery Credit

CNA: Zach Main (en)

Additional Advisory Data

SourceTimeEvent
ADP2026-10-20T00:00:00.000ZCVE-2026-96656 added to CISA KEV

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