CVE-2021-42835

HIGH

Plex Media Server < 1.25.0.5282 - TOCTOU Race Condition

Title source: rule
STIX 2.1

Description

An issue was discovered in Plex Media Server through 1.24.4.5081-e362dc1ee. An attacker (with a foothold in a endpoint via a low-privileged user account) can access the exposed RPC service of the update service component. This RPC functionality allows the attacker to interact with the RPC functionality and execute code from a path of his choice (local, or remote via SMB) because of a TOCTOU race condition. This code execution is in the context of the Plex update service (which runs as SYSTEM).

Exploits (1)

nomisec WORKING POC 6 stars
by netanelc305 · poc
https://github.com/netanelc305/PlEXcalaison

References (4)

Core 4
Core References
Product, Vendor Advisory x_refsource_misc
https://www.plex.tv/media-server-downloads/
Third Party Advisory x_refsource_misc
https://bugsec.com/experts_teams/
Exploit, Third Party Advisory x_refsource_misc
https://ir-on.io/2021/12/02/local-privilege-plexcalation/

Scores

CVSS v3 7.0
EPSS 0.1420
EPSS Percentile 94.5%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-367
Status published
Products (1)
plex/media_server < 1.25.0.5282
Published Dec 08, 2021
Tracked Since Feb 18, 2026