ImpressCMS up to 2.0.3 Custom Tag renderWithPhp code injection

Summaryinfo

A vulnerability classified as problematic has been found in ImpressCMS up to 2.0.3. This affects the function renderWithPhp of the component Custom Tag Module. The manipulation leads to code injection. This vulnerability is referenced as CVE-2026-73679. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in ImpressCMS up to 2.0.3. It has been rated as problematic. This issue affects the function renderWithPhp of the component Custom Tag Module. The manipulation with an unknown input leads to a code injection vulnerability. Using CWE to declare the problem leads to CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-73679 since 08/13/2026. The exploitation is known to be easy. The attack may be initiated remotely. The exploitation requires an enhanced level of successful authentication. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/14/2026). The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• ImpressCMS

Version

• 2.0.0
• 2.0.1
• 2.0.2
• 2.0.3

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CPE 2.2info

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