CVE-2021-41177

moderate-risk
Published 2021-10-25

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`.

Do I need to act?

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0.62% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
8
CVSS 8.1/10 High
NETWORK / LOW complexity

Affected Products (1)

Affected Vendors

Nextcloud

References (8)

Third Party Advisory https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fj39-4...
Patch https://github.com/nextcloud/server/pull/28728
Permissions Required https://hackerone.com/reports/1265709
Third Party Advisory https://security.gentoo.org/glsa/202208-17
Third Party Advisory https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fj39-4...
Patch https://github.com/nextcloud/server/pull/28728
Permissions Required https://hackerone.com/reports/1265709
Third Party Advisory https://security.gentoo.org/glsa/202208-17
35
/ 100
moderate-risk
Severity 28/34 · Critical
Exploitability 2/34 · Minimal
Exposure 5/34 · Minimal