Nextcloud Server 22-27: BruteForce OAuth2 Client Secrets (CVE202339958)
CVE-2023-39958 Published on August 10, 2023
Missing brute force protection on password reset token OAuth2 API controller
Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 22.0.0 and prior to versions 22.2.10.13, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, missing protection allows an attacker to brute force the client secrets of configured OAuth2 clients. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 22.2.10.13, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.
Vulnerability Analysis
CVE-2023-39958 is exploitable with network access, and does not require authorization privileges or user interaction. 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
Improper Restriction of Excessive Authentication Attempts
The software does not implement sufficient measures to prevent multiple failed authentication attempts within in a short time frame, making it more susceptible to brute force attacks.
Products Associated with CVE-2023-39958
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Affected Versions
nextcloud security-advisories:- Version >= 22.0.0, < 22.2.10.13 is affected.
- Version >= 23.0.0, < 23.0.12.8 is affected.
- Version >= 24.0.0, < 24.0.12.5 is affected.
- Version >= 25.0.0, < 25.0.9 is affected.
- Version >= 26.0.0, < 26.0.4 is affected.
- Version >= 27.0.0, < 27.0.1 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.