CVE-2026-96656

Plex Media Server arbitrary file write

At a glance

Severity: HIGH 8.6
Exploitation: Known exploited (CISA KEV) · added 2026-10-20
Exploited per ENISA since 2026-10-20
EPSS: EPSS 1.79 % · percentile 78 (2026-10-27)
State: PUBLISHED
Published: 2026-09-23
Updated: 2026-10-21
Assigner: cisa-cg
NVD status: Analyzed

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.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	HIGH 8.6	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	cisa-cg
CVSS 3.1	HIGH 7.2	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H	cisa-cg
CVSS 4.0	HIGH 8.6	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	NVD · 9119a7d8-5eab-497f-8521-727c672e3725 (Secondary)
CVSS 3.1	HIGH 7.2	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H	NVD · 9119a7d8-5eab-497f-8521-727c672e3725 (Secondary)

Weaknesses (CWE)

CWE-73

European references

ENISA EUVD · EUVD-2026-85370
GCVE · GCVE-0-2026-96656

Affected configurations (NVD CPE)

cpe:2.3:a:plex:media_server:*:*:*:*:*:*:*:* < 1.43.3.10861

Affected products

Product	Versions
Plex · Media Server	affected 0 < 1.43.3.10861 ; unaffected 1.43.3.10861

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
CISA Known Exploited Vulnerabilities	CC0 1.0
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD