CVE-2026-118694

python-markdown2 through 2.5.5 Denial of Service via Unclosed Inline Link Destinations

Published Oct 28, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title python-markdown2 through 2.5.5 Denial of Service via Unclosed Inline Link Destinations
First Time appeared Python-markdown2 Project
Python-markdown2 Project python-markdown2
Weaknesses CWE-407
CPEs cpe:2.3:a:python-markdown2_project:python-markdown2:*:*:*:*:*:*:*:*
Vendors & Products Python-markdown2 Project
Python-markdown2 Project python-markdown2
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 29, 2026, 5:22 PM
Reserved
Oct 28, 2026, 5:31 PM
Status
Deferred
Published
Oct 28, 2026, 10:17 PM
Modified
Oct 29, 2026, 6:17 PM
Severity
Important
Public date
Oct 28, 2026, 9:11 PM