CVE•Published 2026-03-24•Modified 2026-04-08•0 articles on news•5 live references•NVD data

CVE-2026-33347Thephpleague · Commonmark

Vulnerability data via NVD (ingested)

CVSS v3.1

6.1

MEDIUM

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

EPSS percentile

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Weaknesses (CWE)

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CWE-185Incorrect Regular Expression CWE-918Server-Side Request Forgery (SSRF)

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.

Timeline

Published 2026-03-24

Modified 2026-04-08

External references

NVD MITRE Exploit-DB Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-33347

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Thephpleague Commonmark"

All exposed Thephpleague Commonmark instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Commonmark"

HTTP body or banner mentions "Commonmark" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-33347