ImpressCMS contains an authenticated remote code execution vulnerability in the custom tag module that allows authenticated administrators to execute arbitrary PHP code by storing a malicious payload in a custom tag with PHP type enabled. The application decodes HTML-encoded content via undoHtmlSpecialChars() before passing it to eval() in the renderWithPhp() method, bypassing HTML Purifier sanitization, and the payload is triggered on every frontend page load through the preload event system.
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Fixes

Solution

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Workaround

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History

Fri, 14 Aug 2026 19:15:00 +0000

Type Values Removed Values Added
Description ImpressCMS contains an authenticated remote code execution vulnerability in the custom tag module that allows authenticated administrators to execute arbitrary PHP code by storing a malicious payload in a custom tag with PHP type enabled. The application decodes HTML-encoded content via undoHtmlSpecialChars() before passing it to eval() in the renderWithPhp() method, bypassing HTML Purifier sanitization, and the payload is triggered on every frontend page load through the preload event system.
Title ImpressCMS Authenticated RCE via PHP Custom Tag eval()
Weaknesses CWE-94
References
Metrics cvssV3_1

{'score': 7.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-14T19:03:24.913Z

Reserved: 2026-08-13T15:15:17.100Z

Link: CVE-2026-73679

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-14T19:18:01.610

Modified: 2026-08-14T19:18:01.610

Link: CVE-2026-73679

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses