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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 3
https://github.com/thephpleague/commonmark/commit/59fb075d2101740c337c7216e3f32…
security-advisories@github.com
https://github.com/thephpleague/commonmark/releases/tag/2.8.2
security-advisories@github.com
https://github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g…
security-advisories@github.com