CVE-2021-33586: Inspircd

Medium severity, CVSS 4.3. EPSS: 0.9% chance of exploitation in the next 30 days.

InspIRCd 3.8.0 through 3.9.x before 3.10.0 allows any user (able to connect to the server) to access recently deallocated memory, aka the "malformed PONG" issue.

Affected products

• Inspircd Inspircd: from 3.8.0, before 3.10.0 (fixed in 3.10.0)

Published 2021-05-27. Last modified 2026-06-17.