Description
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0.
Analysis and contextual insights are available on OpenCVE Cloud.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-29pj-957v-52mc | league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes |
References
History
Fri, 07 Aug 2026 01:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Thephpleague
Thephpleague commonmark |
|
| Vendors & Products |
Thephpleague
Thephpleague commonmark |
Thu, 06 Aug 2026 22:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0. | |
| Title | league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes | |
| Weaknesses | CWE-692 CWE-79 CWE-86 |
|
| References |
| |
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-08-06T20:30:32.045Z
Reserved: 2026-08-06T19:56:23.724Z
Link: CVE-2026-71478
No data.
No data.
No data.
OpenCVE Enrichment
Updated: 2026-08-07T01:15:04Z
Github GHSA