CVE-2026-86433
8.7
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
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| thephpleague | commonmark | 1.5.0 < 2.8.4 | affected |
| thephpleague | commonmark | 2.8.4 | unaffected |
Weaknesses
- CWE-407: Inefficient Algorithmic Complexity
References
- https://github.com/thephpleague/commonmark/security/advisories/GHSA-g2gp-3wwq-f4ph
- https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-attributes
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