Actively exploited

CVE-2026-96656 Plex Media Server External Control of File Name or Path Vulnerability

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.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment

CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 20 Oct 2026.
Rated High severity (CVSS 7.2, scored by Vendor).

The Vulnerability

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.

Affected Versions

Product	Versions
Plex Media Server	before 1.43.3.10861

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

1
Find it
Search your asset inventory and external attack surface for Plex Media Server. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management
2
Fix it
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.
Vulnerability Management
3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response
4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated high, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 23 Oct 2026 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited Plex Flaws

All 5 exploited Plex vulnerabilities

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2026-96656 and every other exploited flaw on the list.

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Evidence

PREVENTION

DETECTION & MITIGATION

GRC

INCIDENT RESPONSE

CLOUD SECURITY

CRITICAL INFRASTRUCTURE

REGULATED SERVICES

PUBLIC SERVICES

COMMERCIAL

THREAT INTELLIGENCE

MANAGED SECURITY

NETWORK & CLOUD

RISK & COMPLIANCE

DATA & APPLICATIONS

PEOPLE & EMAIL

FOR VENDORS

CVE-2026-96656 Plex Media Server External Control of File Name or Path Vulnerability

Should You Worry?

What It Is

Affected Versions

What To Do Now

Find it

Fix it

Hunt for compromise

Prove it is fixed

Vendor Advisories

The Compliance Clock

More Exploited Plex Flaws

Not Sure If You Are Exposed?

Sources