Description
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translate between character positions and byte positions, and the Autolink extension can also copy and validate the remaining line at every URL-like prefix, allowing an attacker who can submit Markdown for conversion to consume disproportionate CPU time with a comparatively small request. 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
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Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-2q4p-g7hv-5rgv | league/commonmark: Quadratic-time denial of service when parsing crafted Markdown |
References
History
Fri, 07 Aug 2026 01:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Thephpleague
Thephpleague commonmark |
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| 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 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translate between character positions and byte positions, and the Autolink extension can also copy and validate the remaining line at every URL-like prefix, allowing an attacker who can submit Markdown for conversion to consume disproportionate CPU time with a comparatively small request. This issue is fixed in 2.9.0. | |
| Title | league/commonmark: Quadratic-time denial of service when parsing crafted Markdown | |
| Weaknesses | CWE-1050 CWE-407 |
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| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-08-06T20:37:17.488Z
Reserved: 2026-08-06T19:56:23.725Z
Link: CVE-2026-71488
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OpenCVE Enrichment
Updated: 2026-08-07T01:15:04Z
Github GHSA