What’s Vulnerable › Vulnerabilities

CVE-2023-28643: Potential share collision for recipients when caching is enabled in nextcloud server

• Severity: high (CVSS 8.8 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: 2023-03-30 · updated 2026-06-17
• Weakness: CWE-706

Description

Nextcloud server is an open source home cloud implementation. In affected versions when a recipient receives 2 shares with the same name, while a memory cache is configured, the second share will replace the first one instead of being renamed to `{name} (2)`. It is recommended that the Nextcloud Server is upgraded to 25.0.3 or 24.0.9. Users unable to upgrade should avoid sharing 2 folders with the same name to the same user.

Affected products

• Nextcloud Server: from 24.0.0 before 24.0.9; from 25.0.0 before 25.0.3 — fixed in 24.0.9, 25.0.3

How to fix

Upgrade to a fixed version: Nextcloud Server 24.0.9, 25.0.3. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hhq4-4pr8-wm27
• https://github.com/nextcloud/server/issues/34015
• https://github.com/nextcloud/server/pull/36047
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hhq4-4pr8-wm27
• https://github.com/nextcloud/server/issues/34015
• https://github.com/nextcloud/server/pull/36047

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