What’s Vulnerable › Vulnerabilities

CVE-2024-52521: Nextcloud Server has a potential hash collision for background jobs could skip queuing them

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-11-15 · updated 2026-06-17
• Weakness: CWE-328

Description

Nextcloud Server is a self hosted personal cloud system. MD5 hashes were used to check background jobs for their uniqueness. This increased the chances of a background job with arguments falsely being identified as already existing and not be queued for execution. By changing the Hash to SHA256 the probability was heavily decreased. It is recommended that the Nextcloud Server is upgraded to 28.0.10, 29.0.7 or 30.0.0.

Affected products

• Nextcloud Server: from 28.0.0 before 28.0.10; from 29.0.0 before 29.0.7 — fixed in 28.0.10, 29.0.7

How to fix

Upgrade to a fixed version: Nextcloud Server 28.0.10, 29.0.7. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-2q6f-gjgj-7hp4
• https://github.com/nextcloud/server/commit/a933ba1fdba77e7d8c6b8ff400e082cf853ea46d
• https://github.com/nextcloud/server/pull/47769

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