Vulnerability in Plex Media Server
CVE-2026-96656
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.018 (78.3th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 78th percentile — 78.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.018 · change: +0.014
Affected products
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
- 9119a7d8-5eab-497f-8521-727c672e3725 (release-notes, Release Notes)
- 9119a7d8-5eab-497f-8521-727c672e3725 (VDB Entry, Third Party Advisory, vdb-entry)
- 9119a7d8-5eab-497f-8521-727c672e3725 (Third Party Advisory, third-party-advisory)
- 9119a7d8-5eab-497f-8521-727c672e3725 (Third Party Advisory, third-party-advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Third Party Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-96656?
- CVE-2026-96656 is a high-severity vulnerability in Plex Media Server, classified under External Control of File Name or Path. CVSS score: 7.2/10. Published 2026-09-23.
- How severe is CVE-2026-96656?
- High severity. CVSS v3 base score is 7.2 out of 10.
- Is CVE-2026-96656 known to be exploited?
- Yes. CVE-2026-96656 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-10-20), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.