TYPO3-EXT-SA-2026-014: Remote Code Execution in extension "HTML5 Video Player vs. Powermail" (html5videoplayer_powermail)
It has been discovered that the extension "HTML5 Video Player vs. Powermail" (html5videoplayer_powermail) is vulnerable to Remote Code Execution.
- Release Date: August 25, 2026
- Component Type: Third party extension. This extension is not a part of the TYPO3 default installation.
- Component: "HTML5 Video Player vs. Powermail" (html5videoplayer_powermail)
- Composer Package Name: lochmueller/html5videoplayer-powermail
- Vulnerability Type: Insecure Deserialization
- Affected Versions: 0.2.1 and below
- Severity: Critical
- Suggested CVSS v4.0: AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- References: CVE-2026-77138, CWE-502
Problem Description
The extension fails to safely process untrusted client input of an attacker-controlled cookie directly to PHP's unserialize(). A remote, unauthenticated attacker can supply a crafted serialized payload to trigger PHP Object Injection, leading to Remote Code Execution on the TYPO3 server.
Solution
All versions of this extension that are known to be vulnerable will no longer be available for download from the TYPO3 Extension Repository, because the extension is outdated and unmaintained.
Please uninstall and delete the extension folder from your installation and search on the TYPO3 Extension Repository for alternative extensions.
Credits
Thanks to TYPO3 Security Team member Torben Hansen for reporting the vulnerability.
General Advice
Follow the recommendations that are given in the TYPO3 Security Guide.
