The CVE record says URL values in searchOne are not handled correctly, so an attacker can call other plugins' functions and supply their own parameters. Plex describes it as access to internal agent functions over the loopback interface. CISA added it to its Known Exploited Vulnerabilities catalog on 20 October 2026.
What it allows
The CVE record says Plex Media Server before 1.43.3.10861 does not correctly neutralize URL values included in searchOne. This allows an attacker to call other plugins' functions and supply their own parameters. Unlike its neighbours in the chain, the flaw needs no privileges in the CVSS vector.
The researcher explains the setting. The plugin management API under /system/agents/ needs no token for requests from the loopback address, so the forged request from CVE-2026-96652 reaches it.
A check meant to reject unknown identifiers does not stop anything, because a decorator discards its return value. The identifier is then placed into an internal URL without encoding, so the characters ? and # let an attacker forge calls to any plugin function.
In the researcher's chain, one forged call asks the server to fetch an address that begins with 127.0.0.1. The server then attaches the owner's admin token to the request. Plex's own table lists this CVE as access to internal agent functions over the loopback interface.
Plex2Shell is the name for the chain of CVE-2026-96652, CVE-2026-96654, CVE-2026-96655 and CVE-2026-96656. CISA's entry for each one says it can be chained with the other three. Our Plex2Shell attack chain explainer shows the step before and after this one.
In our checks on 23 October 2026, a GitHub search for this CVE id returned 3 repositories, the earliest created on 17 October. We did not run or link any of them.
Who is affected
Plex Media Server before build 1.43.3.10861, according to the CVE record. Plex says 1.43.3.10861 and later are not affected.
Plex's post title says 1.43.2 and earlier, while its 19 October update gives the build number as the cutoff. Use the build number. The researcher's README names builds up to 1.43.3.10828 as vulnerable, so an early 1.43.3 build can still be affected.
Plex's update guide covers Windows, macOS, Linux, NAS devices and Docker. Plex says an internet-reachable server older than 1.43.3.10861 should be assumed possibly compromised.
Timeline
- 1 Sep 2026
Plex announces Plex Media Server 1.43.3 as a security release and says CVEs have been requested.
- 23 Sep 2026
The CVE record is published, with CISA as the CVE numbering authority.
- 16 Oct 2026
A public proof of concept is released, according to Plex.
- 19 Oct 2026
Plex publishes the CVE details and says the flaws are being actively and widely exploited.
- 20 Oct 2026
CISA adds the CVE to the Known Exploited Vulnerabilities catalog.
- 23 Oct 2026
The CISA due date for US federal agencies.
What to do
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Check your version
Open Plex Web, go to Settings, then General, and read the version. Anything older than 1.43.3.10861 is affected. Compare all four numbers of the build, not only 1.43.3.
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Update now
Install Plex Media Server 1.43.3.10861 or later. On a NAS the package manager may be behind, so Plex says to download the package from its Downloads page and install it by hand.
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Cut exposure
If you do not need remote access, turn it off under Settings, then Remote Access. Plex also advises against forwarding port 32400 directly unless you need it.
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Do not probe the agent paths
Do not send requests to /system/agents/ paths to test a server. Read the version in Plex Web. If you find any sign of compromise, remember that the chain can end with the owner's admin token stolen, so sign out of all devices and change your Plex password.
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Rebuild if you cannot rule out a compromise
Plex advises a clean installation instead of reusing the old data directory. Sign out of all devices in your Plex account, change the password, and treat anything the Plex service account could reach as exposed.
What Brandefense can do
- Scan your domain in Brandefense Atlas, free
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- Vulnerability Intelligence
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Frequently Asked Questions
Is CVE-2026-96654 being exploited?
Plex says the flaws in this chain are being actively and widely exploited, and CISA added CVE-2026-96654 to its Known Exploited Vulnerabilities catalog on 20 October 2026. CISA lists use in ransomware campaigns as unknown.
Which Plex Media Server version fixes it?
Plex Media Server 1.43.3.10861 and later. Check Settings, then General, in Plex Web, and compare all four numbers of the build.
Do I need to turn off remote access?
Plex advises turning off Remote Access if you do not need it and not forwarding port 32400 directly unless you need it. Updating is still required.
What are plugin functions in Plex Media Server?
Plex Media Server runs metadata and agent code as plugins. The CVE record says this flaw lets an attacker call other plugins' functions and choose their own parameters.
Why does it need CVE-2026-96652?
The researcher says the plugin API opens without a token only for requests from the server itself. The request forgery in CVE-2026-96652 makes an outside request look like one from the server.
Sources
- Important security update for Plex Media Server v1.43.2 and earlierPlex
- Known Exploited Vulnerabilities catalogCISA
- CVE-2026-96654CVE Program
- CVE-2026-96654NVD
- CWE-84: Improper Neutralization of Encoded URI Schemes in a Web PageMITRE
- Plex2Shell: Unauthenticated RCE in Plex Media Serverzmain.info (researcher)
