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CVE-2020-5741

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in Plex Media Server. For every flaw being used in attacks, see Exploited flaws; for Plex’s, see Plex flaws being used in attacks.

CVE-2020-5741 is a security flaw in Plex Media Server, software for streaming your own films and music around the house. Opening a booby-trapped file can let an attacker run their own code through Plex Media Server. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 10 Mar 2023.[1]

Plex Media Server is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Plex has published a fix or advice.

Description

CISA calls it a remote code execution in Plex Media Server. In its words: “Plex Media Server contains a remote code execution vulnerability that allows an attacker with access to the server administrator's Plex account to upload a malicious file via the Camera Upload feature and have the media server execute it.”[1]

The underlying weakness is deserialization of untrusted data (CWE-502), in MITRE’s list of common software weaknesses.[2]

It scores 7.2 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]

Affected versions

NVD’s record doesn’t list version ranges for it; Plex’s advisory has them[3]. CISA names the product as Plex Media Server.

Every device with Plex Media Server needs the update.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 10 Mar 2023, 1,036 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 31 Mar 2023 to fix it.[1]

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 73%. That’s in the top 1% of the flaws it scores.[4]

CISA assesses it as not automatable: each attack takes some work.

CISA doesn’t say who was attacked, or how.

Fix

Plex has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]

  1. Update Plex Media Server now.Install the latest update from Plex on every device that has it, and restart when asked. Then turn on automatic updates, so the next fix arrives on its own.
  2. If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 7.2.[2]
CISA adds it to its catalog of flaws known to be used in attacks.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 73%.[4]

See also

Other Plex Media Server flaws

  • CVE-2026-96656: external control of file name or path ·
  • CVE-2026-96655: server-side request forgery (SSRF) ·
  • CVE-2026-96654: improper neutralization of encoded URI schemes in a web page ·
  • CVE-2026-96652: server-side request forgery (SSRF) ·

Other deserialization of untrusted data flaws

  • CVE-2021-23758, Ajax.NET Professional: deserialization of untrusted data ·
  • CVE-2026-63077, JetBrains TeamCity: deserialization of untrusted data ·
  • CVE-2026-50522, Microsoft SharePoint: deserialization of untrusted data ·
  • CVE-2026-58644, Microsoft SharePoint: deserialization of untrusted data ·
  • CVE-2026-45659, Microsoft SharePoint Server: deserialization of untrusted data ·

Added the same day

Every Plex flaw on CISA’s list · Everything added in March 2023

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Plex Media Server Remote Code Execution Vulnerability”. Known Exploited Vulnerabilities Catalog, added 10 Mar 2023.
  2. ^ National Institute of Standards and Technology. “CVE-2020-5741 Detail”. National Vulnerability Database, published 8 May 2020.
  3. ^ Plex. Advisories and fixes: forums.plex.tv.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.729, percentile 99.5, 31 Oct 2026.
  5. CVE Program. “CVE-2020-5741”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.