CVE-2021-41177

Name: CVE-2021-41177
Creator: NVD / NIST
Published: 2021-10-25T22:15:07.847+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 1.50%

Last modified Jun 17, 2026

CVE-2021-41177 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. 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. EPSS estimates a 1.50% chance of exploitation in the next 30 days.

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`.

Metrics

CVSS 3.1

8.1/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS Probability

1.50%

71.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-799

Affected Software

Vendor	Product	Versions
Nextcloud	Nextcloud Server	< 20.0.13
Nextcloud	Nextcloud Server	>= 21.0.0, < 21.0.5
Nextcloud	Nextcloud Server	>= 22.0.0, < 22.2.0

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fj39-4qx4-m3f2Third Party Advisory
https://github.com/nextcloud/server/pull/28728Patch, Third Party Advisory
https://hackerone.com/reports/1265709Permissions Required, Third Party Advisory
https://security.gentoo.org/glsa/202208-17Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fj39-4qx4-m3f2Third Party Advisory
https://github.com/nextcloud/server/pull/28728Patch, Third Party Advisory
https://hackerone.com/reports/1265709Permissions Required, Third Party Advisory
https://security.gentoo.org/glsa/202208-17Third Party Advisory

Timeline

Published: Oct 25, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-41177?

How severe is CVE-2021-41177?

CVE-2021-41177 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 1.50% probability of exploitation in the next 30 days.

How do I fix CVE-2021-41177?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-41177?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST