title: Argo CD vulnerable to Bypassing of Rate Limit and Brute Force Protection Using Cache Overflow
description: Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. Prior to versions 2.8.13, 2.9.9, and 2.10.4, an attacker can effectively bypass the rate limit and brute force protections by exploiting the application's weak cache-based mechanism. This loophole in security can be combined with other vulnerabilities to attack the default admin account. This flaw undermines a patch for CVE-2020-8827 intended to protect against brute-force attacks. The application's brute force protection relies on a cache mechanism that tracks login attempts for each user. This cache is limited to a `defaultMaxCacheSize` of 1000 entries. An attacker can overflow this cache by bombarding it with login attempts for different users, thereby pushing out the admin account's failed attempts and effectively resetting the rate limit for that account. This is a severe vulnerability that enables attackers to perform brute force attacks at an accelerated rate, especially targeting the default admin account. Users should upgrade to version 2.8.13, 2.9.9, or 2.10.4 to receive a patch.
problem types: CWE-307: Improper Restriction of Excessive Authentication Attempts
affected:
{
vendor: argoproj
product: argo-cd
versions:
version: < 2.8.13, status: affected
version: >= 2.9.0, < 2.9.9, status: affected
version: >= 2.10.0, < 2.10.4, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 7.5
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: HIGH
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
version: 3.1
]