# CVE-2026-33347

## Summary

- **CVE ID:** CVE-2026-33347
- **Severity:** MEDIUM
- **CVSS Score:** 6.3 (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)
- **CWE:** CWE-79, CWE-185, CWE-918
- **Published:** Mar 24, 2026
- **Last Modified:** Mar 26, 2026

## Description

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.

## Affected Products

- thephpleague — commonmark (>= 2.3.0, < 2.8.2)

## References

- [CNA](https://github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g3f5)
- [CNA](https://github.com/thephpleague/commonmark/commit/59fb075d2101740c337c7216e3f32b36c204218b)
- [CNA](https://github.com/thephpleague/commonmark/releases/tag/2.8.2)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.24%
- **EPSS Percentile:** 15.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._