Nextcloud Server DNS Rebinding SSRF (v25-27)
CVE-2023-48306 Published on November 21, 2023
Nextcloud Server DNS pin middleware can be tricked into DNS rebinding allowing SSRF
Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.11, 26.0.6, and 27.1.0 of Nextcloud Server and starting in version 22.0.0 and prior to versions 22.2.10.16, 23.0.12.11, 24.0.12.7, 25.0.11, 26.0.6, and 27.1.0 of Nextcloud Enterprise Server, the DNS pin middleware was vulnerable to DNS rebinding allowing an attacker to perform SSRF as a final result. Nextcloud Server 25.0.11, 26.0.6, and 27.1.0 and Nextcloud Enterprise Server 22.2.10.16, 23.0.12.11, 24.0.12.7, 25.0.11, 26.0.6, and 27.1.0 contain patches for this issue. No known workarounds are available.
Vulnerability Analysis
CVE-2023-48306 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a small impact on integrity and availability.
Weakness Type
What is a SSRF Vulnerability?
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
CVE-2023-48306 has been classified to as a SSRF vulnerability or weakness.
Products Associated with CVE-2023-48306
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Affected Versions
nextcloud security-advisories:- Version >= 22.0.0, < 22.2.10.16 is affected.
- Version >= 23.0.0, < 23.0.12.11 is affected.
- Version >= 24.0.0, < 24.0.12.7 is affected.
- Version >= 25.0.0, < 25.0.11 is affected.
- Version >= 26.0.0, < 26.0.6 is affected.
- Version >= 27.0.0, < 27.1.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.