CVE-2021-42835

Name: CVE-2021-42835
Creator: NVD / NIST
Published: 2021-12-08T15:15:10.18+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7/10EPSS 1.17%

Last modified Jun 17, 2026

CVE-2021-42835 is a high-severity vulnerability rated 7/10 on the CVSS scale. 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. EPSS estimates a 1.17% chance of exploitation in the next 30 days.

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).

Metrics

CVSS 3.1

7/10

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.17%

63.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-367

Affected Software

Vendor	Product	Versions
Plex	Media Server	< 1.25.0.5282

References

https://bugsec.com/experts_teams/Third Party Advisory
https://forums.plex.tv/t/security-regarding-cve-2021-42835/761510Vendor Advisory
https://ir-on.io/2021/12/02/local-privilege-plexcalation/Exploit, Third Party Advisory
https://www.plex.tv/media-server-downloads/Product, Vendor Advisory
https://bugsec.com/experts_teams/Third Party Advisory
https://forums.plex.tv/t/security-regarding-cve-2021-42835/761510Vendor Advisory
https://ir-on.io/2021/12/02/local-privilege-plexcalation/Exploit, Third Party Advisory
https://www.plex.tv/media-server-downloads/Product, Vendor Advisory

Timeline

Published: Dec 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42835?

How severe is CVE-2021-42835?

CVE-2021-42835 has a CVSS score of 7/10 (HIGH severity). The EPSS model estimates a 1.17% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42835?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-42835?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST