CVE-2026-86433
commonmark 1.5.0 before 2.8.4 Denial of Service via Attributes
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-407 |
| Vendor | thephpleague |
| Product | commonmark |
| Published | Sep 7, 2026 |
| Last Updated | Sep 8, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
thephpleague / commonmark
1.5.0 < 2.8.4
References
Credits
GrahamCampbell