CVE-2026-96656
Plex Media Server arbitrary file write
Updated
- CVSS 4.0
- 8.6 HIGH
- EPSS
- 1.8% (79th pct)
- CISA KEV
- Exploited
- Published
- 2026-09-23
- Weakness
- CWE-73
Plex Media Server External Control of File Name or Path Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.
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.
CISA 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
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.
Key Findings
as of 2026-11-12- CISA added CVE-2026-96656 to the KEV catalog 27 days after its CVE record was published. The median for entries added in 2026 so far is 12 days.
- It is one of 5 Plex entries in the CISA KEV catalog, and one of 4 added in 2026.
- Its current EPSS score (1.8%) is higher than that of 7% of CISA KEV entries.
Severity
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NOpen in CVSS calculator CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:HOpen in CVSS calculator Affected Products
| Vendor | Product | Affected versions |
|---|---|---|
| Plex | Plex Media Server | 0 to <1.43.3.10861 1.43.3.10861 (unaffected) |
References
4 linksRecord Details
- Published
- 2026-09-23
- Last updated
- 2026-10-21
- Assigner (CNA)
- cisa-cg
- Credited to
- Zach Main
More from Plex
CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). Alert titles and links from CISA cybersecurity alerts. This site is not affiliated with or endorsed by MITRE, NVD, CISA, or FIRST.