CVE-2026-118694

High

Description

python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.

SeverityHigh

CVSS7.5

Exploit probability—

ProductTrentm Python-markdown2

PublishedOct 28, 2026

First seenNov 4, 2026

Weakness typeCWE-407CWE-407

How to fix

Patches

github.com/trentm/python-markdown2/pull/751

Affected products

Product	Affected versions	Fixed in
trentm python-markdown2	v ≤ 2.5.5	—

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