Nextcloud server is an open source, personal cloud implementation. In affected versions a malicious user could try to reset the password of another user and then brute force the 62^21 combinations for the password reset token. As of commit 704eb3aa password reset attempts are now throttled. Note that 62^21 combinations would significant compute resources to brute force. None the less it is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. There are no known workarounds for this vulnerability.
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.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Nextcloud_server | Nextcloud | 21.0.0 (including) | 21.0.9.10 (excluding) |
| Nextcloud_server | Nextcloud | 22.0.0 (including) | 22.2.10.10 (excluding) |
| Nextcloud_server | Nextcloud | 23.0.0 (including) | 23.0.12.5 (excluding) |
| Nextcloud_server | Nextcloud | 24.0.0 (including) | 24.0.10 (excluding) |
| Nextcloud_server | Nextcloud | 25.0.0 (including) | 25.0.4 (excluding) |
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]