CVE-2021-42835
HIGHDescription
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).
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 65% of all known CVEs.
References
Related Vulnerabilities
Other CWE-367 (TOCTOU Race Condition) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-36980 | High | 8.1 | 83% | - | Fix |
| CVE-2024-30088 | High | 7.0 | 68% | KEV + Ransom | Fix |
| CVE-2004-0594 | Medium | 5.1 | 55% | - | Fix |
| CVE-2024-50379 | Critical | 9.8 | 44% | - | Fix |
| CVE-2023-38146 | High | 8.8 | 39% | - | Fix |
| CVE-2024-0132 | Critical | 9.0 | 38% | - | Fix |
Common questions
How do I fix CVE-2021-42835?
Upgrade Plex Media Server to 1.25.0.5282 or later.
Is CVE-2021-42835 being actively exploited?
Not that we know of. CVE-2021-42835 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.2% is the estimated probability that it will be exploited in the next 30 days. That is higher than 65% of all scored CVEs.
How severe is CVE-2021-42835?
CVE-2021-42835 has a CVSS v3 base score of 7.0, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-42835 affect?
Published advisories record a fix for Plex Media Server (Windows application). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-42835
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.