CVE-2026-86428
commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes
- State
- Published
- Severity
- 8.7 High
- Published
- Sep 7, 2026
- Updated
- Oct 8, 2026
- Reserved
- Sep 7, 2026
Description
commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
Weaknesses
- CWE-407 Inefficient Algorithmic Complexity
Affected Products
| Product | Versions |
|---|---|
commonmarkthephpleague |
|
References
- GitHub Security Advisory (GHSA-8rr7-cvq3-gmfh)vendor-advisory
- VulnCheck Advisory: commonmark 1.5.0 before 2.10.0 Denial of Service via Attributesthird-party-advisory
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