title: Rate-limits not working on instances without configured memory cache backend
description: Nextcloud is an open-source, self-hosted productivity platform. Prior to versions 20.0.13, 21.0.5, and 22.2.0, Nextcloud Server did not implement a database backend for rate-limiting purposes. Any component of Nextcloud using rate-limits (as as `AnonRateThrottle` or `UserRateThrottle`) was thus not rate limited on instances not having a memory cache backend configured. In the case of a default installation, this would notably include the rate-limits on the two factor codes. It is recommended that the Nextcloud Server be upgraded to 20.0.13, 21.0.5, or 22.2.0. As a workaround, enable a memory cache backend in `config.php`.
problem types: CWE-799: Improper Control of Interaction Frequency
affected:
{
product: security-advisories
vendor: nextcloud
versions:
status: affected, version: < 20.0.13
status: affected, version: >= 21.0.0, < 21.0.5
status: affected, version: < 22.2.0
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 8.1
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
version: 3.1
]