CVE Vulnerabilities

CVE-2021-22915

Improper Restriction of Excessive Authentication Attempts

Published: Jun 11, 2021 | Modified: Nov 07, 2023
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N
RedHat/V2
RedHat/V3
Ubuntu

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.

Weakness

The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame, making it more susceptible to brute force attacks.

Affected Software

Name Vendor Start Version End Version
Nextcloud_server Nextcloud * *
Nextcloud_server Nextcloud 20.0.0 *
Nextcloud_server Nextcloud 21.0.0 *

Potential Mitigations

  • Common protection mechanisms include:

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

  • Consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator. [REF-45]

References