CVE-2026-96656Plex Media Server arbitrary file write
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.
Overview
Severity
| Score | Severity | Version | Vector String |
|---|---|---|---|
| 8.6 | HIGH | 4.0cisa-cg (CNA) | 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 |
| 7.2 | HIGH | 3.1cisa-cg (CNA) | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
CISA required action
⚡ Known exploited · remediation due Oct 23, 2026
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.
Details
- CVE ID
- CVE-2026-96656
- Status
- Analyzed
- Assigner (CNA)
- cisa-cg
- Published
- Sep 23, 2026
- Last modified
- 2026-10-21 13:09 UTC
- Weaknesses
- CWE-73 · External Control of File Name or Path
Affected Products
As published by the CNA in the CVE record.
PlexMedia Server1 version range
- before 1.43.3.10861
References
- forums.plex.tv https://forums.plex.tv/t/plex-media-server/30447/711
- raw.githubusercontent.com https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-266-01.json
- cve.org https://www.cve.org/CVERecord?id=CVE-2026-96656
- zmain.info https://zmain.info/blog/plex2shell
- boredhackerblog.info https://www.boredhackerblog.info/2026/10/plex-vulnerabilities-being-exploited-in.html
- cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-96656