Answer in brief
CVE-2026-71488 records a High severity (CVSS 7.5) vulnerability in league/commonmark: Quadratic-time denial of service when parsing crafted Markdown. The current sources do not mark it as known exploited. The current feed maps league/commonmark (composer), thephpleague/commonmark (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-71488 records a High severity (CVSS 7.5) vulnerability in league/commonmark: Quadratic-time denial of service when parsing crafted Markdown. The current sources do not mark it as known exploited. The current feed maps league/commonmark (composer), thephpleague/commonmark (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps league/commonmark (composer), thephpleague/commonmark (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| league/commonmarkcomposer | >=0.6.0,<2.9.0 | 2.9.0 |
| thephpleague/commonmarkgeneric | >= 0.6.0, < 2.9.0 | Not reported |
Published upstream
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps league/commonmark (composer), thephpleague/commonmark (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| league/commonmarkcomposer | >=0.6.0,<2.9.0 | 2.9.0 |
| thephpleague/commonmarkgeneric | >= 0.6.0, < 2.9.0 | Not reported |
Published upstream
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.