What’s Vulnerable › Vulnerabilities

CVE-2023-28847: Nextcloud Server missing brute force protection for passwords of password protected share links

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-04-25 · updated 2026-06-17
• Weakness: CWE-307

Description

Nextcloud Server is the file server software for Nextcloud, a self-hosted productivity platform. In Nextcloud Server 24.0.0 prior to 24.0.11 and 25.0.0 prior to 25.0.5; as well as Nextcloud Server Enterprise 23.0.0 prior to 23.0.12.6, 24.0.0 prior to 24.0.11, and 25.0.0 prior to 25.0.5; an attacker is not restricted in verifying passwords of share links so they can just start brute forcing the password. Nextcloud Server 24.0.11 and 25.0.5 and Nextcloud Enterprise Server 23.0.12.6, 24.0.11, and 25.0.5 contain a fix for this issue. No known workarounds are available.

Affected products

• Nextcloud Server: from 23.0.0 before 23.0.12.6; from 24.0.0 before 24.0.11; from 25.0.0 before 25.0.5 — fixed in 23.0.12.6, 24.0.11, 25.0.5

How to fix

Upgrade to a fixed version: Nextcloud Server 23.0.12.6, 24.0.11, 25.0.5. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-r5wf-xj97-3w7w
• https://github.com/nextcloud/server/pull/35057
• https://hackerone.com/reports/1894653
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-r5wf-xj97-3w7w
• https://github.com/nextcloud/server/pull/35057
• https://hackerone.com/reports/1894653

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