What’s Vulnerable › Vulnerabilities

CVE-2023-48307: Nextcloud Mail app vulnerable to Server-Side Request Forgery

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-11-21 · updated 2026-06-17
• Weakness: CWE-918

Description

Nextcloud Mail is the mail app for Nextcloud, a self-hosted productivity platform. Starting in version 1.13.0 and prior to version 2.2.8 and 3.3.0, an attacker can use an unprotected endpoint in the Mail app to perform a SSRF attack. Nextcloud Mail app versions 2.2.8 and 3.3.0 contain a patch for this issue. As a workaround, disable the mail app.

Affected products

• nextcloud Mail: from 1.13.0 before 2.2.8; from 3.0.0 before 3.3.0 — fixed in 2.2.8, 3.3.0

How to fix

Upgrade to a fixed version: nextcloud Mail 2.2.8, 3.3.0. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/mail/pull/8709
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-4pp4-m8ph-2999
• https://hackerone.com/reports/1869714
• https://github.com/nextcloud/mail/pull/8709
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-4pp4-m8ph-2999
• https://hackerone.com/reports/1869714

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