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TI-2021-18016 Aliases CVE-2021-41177

Rate-limits not working on instances without configured memory cache backend

Priority LOW 38CWE-799Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

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`.

Why it matters now

EPSS 0.0155 75th percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 20.0.13, 21.0.5, 22.2.0

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudsecurity-advisoriesbefore 20.0.13; 21.0.0 to before 21.0.5; before 22.2.020.0.13, 21.0.5, 22.2.0Patch availableCNA
  • security-advisories Vendornextcloud Affected before 20.0.13; 21.0.0 to before 21.0.5; before 22.2.0 Fixed in 20.0.13, 21.0.5, 22.2.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*before 20.0.13; 21.0.0 to before 21.0.5; 22.0.0 to before 22.2.0Vulnerablenextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* Versions before 20.0.13; 21.0.0 to before 21.0.5; 22.0.0 to before 22.2.0 Vulnerable ·nextcloud

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 20.0.13, 21.0.5, 22.2.0

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-41177

References

Patch 1

Advisory 3

  • TI-2023-20855 Users can delete external storage mount points CVSS 3.1HIGH 7.7
  • TI-2023-11091 Nextcloud download permissions can be changed by resharer CVSS 3.1HIGH 7.5
  • TI-2023-10624 Nextcloud Server vulnerable to SSRF via filter bypass due to lax checking on IPs CVSS 3.1MEDIUM 5.3
  • TI-2025-37238 Cross-site scripting in Nextcloud CVSS 3.1MEDIUM 6.4
  • TI-2023-11086 nextcloud vulnerable to Uncontrolled Resource Consumption CVSS 3.1MEDIUM 6.5
  • TI-2022-18738 Exception logging in Sharepoint app reveals clear-text connection details CVSS 3.1MEDIUM 6.5
See all 188 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences