---
cve: "CVE-2026-33347"
severity: "MEDIUM"
cvss: 6.3
epss: "0.2%"
vendor: "thephpleague"
kev: false
exploited: false
published: "2026-03-24 20:16:29"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T14:43:56+02:00"
---

# CVE-2026-33347

> 6.3 MEDIUM · 🧪 PoC

## Beschreibung

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like youtube.com.evil passes the allowlist check when youtube.com is an allowed domain. This issue has been patched in version 2.8.2.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N
```

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

## Patch verfügbar (OSV)

- 59fb075d2101740c337c7216e3f32b36c204218b (Commit)

## Referenzen

- <https://github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g3f5>
- <https://github.com/thephpleague/commonmark/commit/59fb075d2101740c337c7216e3f32b36c204218b>
- <https://github.com/thephpleague/commonmark/releases/tag/2.8.2>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-33347) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_