Medium severity6.1NVD Advisory· Published Mar 24, 2026· Updated Apr 8, 2026
CVE-2026-33347
CVE-2026-33347
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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Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
league/commonmarkPackagist | >= 2.3.0, < 2.8.2 | 2.8.2 |
Affected products
2Patches
Vulnerability mechanics
References
5- github.com/thephpleague/commonmark/commit/59fb075d2101740c337c7216e3f32b36c204218bnvdPatchWEB
- github.com/advisories/GHSA-hh8v-hgvp-g3f5ghsaADVISORY
- github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g3f5nvdMitigationVendor AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-33347ghsaADVISORY
- github.com/thephpleague/commonmark/releases/tag/2.8.2nvdProductRelease NotesWEB
News mentions
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