Dashboard / CVE-2026-121438

CVE-2026-121438

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 74/100
Published: 2026-11-03 Modified: 2026-11-07 First seen: 2026-11-03 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
AT: None
VC: None
VI: None
VA: Low

Description

Mistune before 3.3.3 contains a denial of service vulnerability in InlineParser.parse_link that allows attackers to cause quadratic CPU growth by supplying balanced nested brackets. Attackers can submit crafted Markdown with thousands of nested bracket pairs not forming a valid link, triggering repeated _contains_nested_link scans that exhaust CPU in parsing applications.

Weakness Classification (1)

Affected Software (2)

VendorProductVersion
lepture mistune 0 < 3.3.3
lepture mistune 0 < 3.3.3

References & Advisories (3)

Bug Bounty Relevance

74 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

6.9 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

EPSS — Exploitation Probability

0.29%
Raw Score 0.002910
Percentile 22.0%
Date 2026-11-14

EPSS Trend

2026-11-14
0.00291
2026-11-13
0.00291
2026-11-12
0.00291
2026-11-10
0.00291
2026-11-09
0.00291
2026-11-08
0.00291
2026-11-07
0.00291
2026-11-06
0.00291
2026-11-05
0.00291
2026-11-04
0.00291

Intelligence Sources

mitre ref →
nvd ref →

External Links