CVE-2021-22915: Fedoraproject Fedora

Critical severity, CVSS 9.8. EPSS: 1.7% chance of exploitation in the next 30 days.

Nextcloud server before 19.0.11, 20.0.10, 21.0.2 is vulnerable to brute force attacks due to lack of inclusion of IPv6 subnets in rate-limiting considerations. This could potentially result in an attacker bypassing rate-limit controls such as the Nextcloud brute-force protection.

Affected products

• Fedoraproject Fedora: version 33 only; version 34 only
• Nextcloud Nextcloud Server: before 19.0.11 (fixed in 19.0.11); from 20.0.0, before 20.0.10 (fixed in 20.0.10); from 21.0.0, before 21.0.2 (fixed in 21.0.2)

Published 2021-06-11. Last modified 2026-06-17.