CVE Catalog

CVE-2026-118694

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.45%

39th percentile - higher than 39% of all known CVEs

Summary

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.

Risk Assessment

A remote attacker can exhaust server CPU resources by submitting crafted Markdown, potentially causing denial of service for legitimate users.

Recommendation

Update python-markdown2 to a version later than 2.5.5 and consider limiting the size or complexity of processed Markdown.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS