CVE-2026-86433
commonmark 1.5.0 before 2.8.4 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 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.
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-g2gp-3wwq-f4ph)vendor-advisory
- VulnCheck Advisory: commonmark 1.5.0 before 2.8.4 Denial of Service via Attributesthird-party-advisory
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