---
cve: "CVE-2026-73679"
severity: "HIGH"
cvss: 8.6
epss: "1.1%"
vendor: "ImpressCMS"
kev: false
exploited: false
published: "2026-08-14 19:03:24"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-11-02T23:49:42+01:00"
---

# CVE-2026-73679

> 8.6 HIGH · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **VulnCheck**
- State: PUBLISHED
- Stand: 2026-10-01 15:20:39
- CNA-CVSS: **7.2** (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Hoch | good |
| UI Interaktion | Keine | bad |

## Schwachstellen-Klasse

- **CWE-94** — Improper Control of Generation of Code
  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.

## Angriffsmuster (CAPEC)

- [CAPEC-35 — Leverage Executable Code in Non-Executable Files](https://capec.mitre.org/data/definitions/35.html) _(Severity: Very High)_
- [CAPEC-77 — Manipulating User-Controlled Variables](https://capec.mitre.org/data/definitions/77.html) _(Severity: Very High)_
- [CAPEC-242 — Code Injection](https://capec.mitre.org/data/definitions/242.html) _(Severity: High)_

## ATT&CK-Techniken

- [T1027.006 — Obfuscated Files or Information: HTML Smuggling](https://attack.mitre.org/techniques/T1027/006/)
- [T1027.009 — Obfuscated Files or Information: Embedded Payloads](https://attack.mitre.org/techniques/T1027/009/)
- [T1564.009 — Hide Artifacts: Resource Forking](https://attack.mitre.org/techniques/T1564/009/)

## Referenzen

- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-73679/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_