CVE-2026-86433
HIGH
NVD
CVSS Score
7.5
Severity
HIGH
Published
Sep 07, 2026
Vendor
unknown
Description
commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.