CVE-2026-86435
commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote
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 Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.
| CWE | CWE-407 |
| Vendor | thephpleague |
| Product | commonmark |
| Published | Sep 7, 2026 |
| Last Updated | Sep 9, 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