CVE-2021-28994: Kopano Groupware Core

High severity, CVSS 7.5. EPSS: 2% chance of exploitation in the next 30 days.

kopano-ical (formerly zarafa-ical) in Kopano Groupware Core through 8.7.16, 9.x through 9.1.0, 10.x through 10.0.7, and 11.x through 11.0.1 and Zarafa 6.30.x through 7.2.x allows memory exhaustion via long HTTP headers.

Affected products

• Kopano Groupware Core: up to and including 8.7.16; from 9.0.0, up to and including 9.1.0; from 10.0.0, up to and including 10.0.7; from 11.0.0, up to and including 11.0.1
• Zarafa Zarafa: from 6.30.0, up to and including 7.2.6

Published 2021-03-31. Last modified 2026-06-17.