Medium 6.1Published Mar 24, 2026

CVE-2026-33347league/commonmark is a PHP Markdown parser.

Updated under an hour ago (2026-10-19 08:00 UTC)

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It affects thephpleague commonmark. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for thephpleague commonmark

Exploited in the last 30 days

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: 6.1 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79, CWE-185, CWE-918
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

thephpleague commonmark thephpleague:commonmark	from 2.3.0 before 2.8.2	NVD

References

https://github.com/thephpleague/commonmark/commit/59fb075d2101740c337c7216e3f32b36c204218bpatch
https://github.com/thephpleague/commonmark/releases/tag/2.8.2product, release-notes
https://github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g3f5mitigation, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.