CVE-2026-33347

6.1 MEDIUM
Published: March 24, 2026 Modified: April 08, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/thephpleague/commonmark/releases/tag/2.8.2
Source: security-advisories@github.com
Product Release Notes
https://github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g3f5
Source: security-advisories@github.com
Mitigation Vendor Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
6.1 / 10.0
EPSS (Exploit Probability)
0.0%
2th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

thephpleague