CVE-2026-115352

high

Description

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.

References

https://www.vulncheck.com/advisories/mistune-before-3.3.0-quadratic-time-dos-via-unmatched-brackets-in-inline-parser

https://github.com/lepture/mistune/security/advisories/GHSA-xrpv-r66x-8p7j

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-108421

Details

Source: Mitre, NVD

Published: 2026-10-22

Updated: 2026-10-22

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

CVSS v4

Base Score: 8.7

Vector: 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

Severity: High