CVE-2026-115352
Mistune before 3.3.0 Quadratic-Time DoS via Unmatched Brackets in Inline Parser
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
Mistune before 3.3.0 contains an algorithmic complexity vulnerability in the inline link parser that allows unauthenticated attackers to exhaust CPU by submitting long runs of unmatched '[' characters. Attackers can send small markdown payloads that trigger O(N^2) parse_link_text and parse_link_label probing, occupying rendering workers for 30+ seconds per 16 KB input.
| CWE | CWE-407 |
| Vendor | lepture |
| Product | mistune |
| Published | Oct 22, 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
lepture / mistune
0 < 3.3.0
References
Credits
🔍 offset