CVE-2026-96656: Plex Media Server External Control of File Name or Path Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 20 Oct 2026, 27 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 1.8%
EPSS score, percentile 78.2 of all scored records
- How severe?
- 8.6 High
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline 23 Oct 2026. Apply mitigations in accordance with vendor instructions … Full text
- Which versions are affected?
Affected
- before 1.43.3.10861
Unaffected 1.43.3.10861
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
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 due date for this action: 23 October 2026.
Advisories and patches
Linked from CISA's catalog entry
- https://forums.plex.tv/t/important-security-update-for-plex-media-server-v1-43-2-and-earlier/942319
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- 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
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 1.43.3.10861 |
| Unaffected | 1.43.3.10861 |
Versions not listed are: unknown.
Versions the record lists as unaffected: 1.43.3.10861.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this 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.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2026-96656 to its Known Exploited Vulnerabilities (KEV) catalog on 20 Oct 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 23 Oct 2026.
- The CVE record was published on 23 Sep 2026, 27 days before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 8.6 (High), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 1.8% (percentile 78.2), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
Plex 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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-73: External Control of File Name or Path
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 23 Sep 2026 | CVE record published |
| 20 Oct 2026 | Added to CISA KEV |
| 21 Oct 2026 | CVE record last updated |
| 23 Oct 2026 | CISA due date for the required action |
References
More exploited Plex vulnerabilities
- CVE-2026-96652: Plex Media Server Server-Side Request Forgery (SSRF) Vulnerability
- CVE-2026-96654: Plex Media Server Improper Neutralization of Encoded URI Schemes in a Web Page Vulnerability
- CVE-2026-96655: Plex Media Server Server-Side Request Forgery (SSRF) Vulnerability
- CVE-2020-5741: Plex Media Server Remote Code Execution Vulnerability