Server-side Request Forgery (SSRF) Affecting league/commonmark package, versions >=2.3.0, <2.8.2
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PHP-LEAGUECOMMONMARK-15763119
- published25 Mar 2026
- disclosed19 Mar 2026
- creditHuaji
Introduced: 19 Mar 2026
CVE-2026-33347 (opens in a new tab)How to fix?
Upgrade league/commonmark to version 2.8.2 or higher.
Overview
league/commonmark is a PHP-based Markdown parser which supports the full CommonMark spec. It is based on the CommonMark JS reference implementation.
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via the DomainFilteringAdapter process. An attacker can execute arbitrary JavaScript in the context of the user or trigger server-side HTTP requests to attacker-controlled domains by bypassing domain allowlist checks using crafted hostnames.