---
cve: "CVE-2025-46734"
severity: "MEDIUM"
cvss: 6.4
epss: "0.4%"
vendor: "thephpleague"
kev: false
exploited: false
published: "2025-05-05 20:15:21"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-22T00:28:26+02:00"
---

# CVE-2025-46734

> 6.4 MEDIUM · 🧪 PoC

## Beschreibung

league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: 'strip'` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Gering | warn |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- d150f911e0079e90ae3c106734c93137c184f932 (Commit)
- f0d626cf05ad3e99e6db26ebcb9091b6cd1cd89b (Commit)

## Referenzen

- <https://github.com/thephpleague/commonmark/security/advisories/GHSA-3527-qv2q-pfvx>
- <https://github.com/thephpleague/commonmark/commit/f0d626cf05ad3e99e6db26ebcb9091b6cd1cd89b>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2025-46734) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_