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Known exploited vulnerability

CVE-2026-96656

highCVSS 4.0 8.6In CISA KEVEPSS 1.8%Published · Plex

The short answer

CVE-2026-96656 affects Plex Media Server and is rated high (CVSS 8.6). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-10-20: attackers are using it, so patch it first.

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.

Weakness: CWE-73.

Severity

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

Exploited (CISA KEV)

Yes, since Oct 20, 2026

Federal due date Oct 23, 2026

EPSS, next 30 days

1.8%

Higher than 78% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
High
User interaction
None
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says 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…

Affected products

Media Server. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2026-96656 being exploited?

Yes. CISA added CVE-2026-96656 to its Known Exploited Vulnerabilities catalog on 2026-10-20, with a federal remediation due date of 2026-10-23.

How do I fix CVE-2026-96656?

CISA's 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…

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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