CVE-2021-42835 json
An issue was discovered in Plex Media Server through 1.24.4.5081-e362dc1ee.
published 2021-12-08 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-29791
- cvss
- 7.0
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.2%
- EPSS 1.2% chance of exploitation in 30 days, percentile 68%
- public exploits
- 0
- none known
Summary
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).
Patch / fix
- plex media_server 1.25.0.5282
Exploit prediction
1.19% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- ir-on.io https://ir-on.io/2021/12/02/local-privilege-plexcalation/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.0 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.9 | AV:L/AC:M/Au:N/C:C/I:C/A:C |
Classification
- Weakness
-
- CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
References
-
ir-on.io
/2021/12/02/local-privilege-plexcalation/
exploit, third-party-advisory
-
plex.tv
/media-server-downloads/
product, vendor-advisory
-
forums.plex.tv
/t/security-regarding-cve-2021-42835/761510
vendor-advisory
-
bugsec.com
/experts_teams/
third-party-advisory
Sources
- CVE List CVE-2021-42835
- NVD CVE-2021-42835
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