CVE-2026-118694: trentm python-markdown2 (High, CVSS 8.7)

CVE record · updated Oct 29, 2026

CVE-2026-118694Hightrentm python-markdown2

CVSS: 8.7 High (v4.0)
EPSS: 0.5% chance of exploitation in the next 30 days (higher than 39.2% of CVEs)
Exploited in the wild: Not on CISA’s KEV list
Public exploit: None reported in public exploit databases
Weakness: CWE-407
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
Published: Oct 28, 2026

What it is

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.

Description from the National Vulnerability Database.

What to do

Check whether you run trentm python-markdown2, then apply the vendor’s fix or mitigation from the advisories below.

Sources: NVD, FIRST EPSS, CISA KEV, and public exploit databases (availability only). ThreatRoundup reports whether public exploit code exists but never links to it: fake proof-of-concepts that infect security researchers are common. This page updates automatically.