What’s Vulnerable › Vulnerabilities

CVE-2023-25818: Missing brute force protection on password reset token in Nextcloud Server

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-03-27 · updated 2026-06-17
• Weakness: CWE-307

Description

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.

Affected products

• Nextcloud Server: from 21.0.0 before 21.0.9.10; from 22.0.0 before 22.2.10.10; from 23.0.0 before 23.0.12.5; from 24.0.0 before 24.0.10; from 25.0.0 before 25.0.4 — fixed in 21.0.9.10, 22.2.10.10, 23.0.12.5, 24.0.10, 25.0.4

How to fix

Upgrade to a fixed version: Nextcloud Server 21.0.9.10, 22.2.10.10, 23.0.12.5, 24.0.10. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-v243-x6jc-42mp
• https://github.com/nextcloud/server/pull/36489
• https://github.com/nextcloud/server/pull/36489/commits/704eb3aa6cecc0a646f5cca4290b595f493f9ed3
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-v243-x6jc-42mp
• https://github.com/nextcloud/server/pull/36489
• https://github.com/nextcloud/server/pull/36489/commits/704eb3aa6cecc0a646f5cca4290b595f493f9ed3

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