CVE-2025-46603: Dell CloudBoost Auth Bypass Vulnerability

CVE-2025-46603 Overview

CVE-2025-46603 affects Dell CloudBoost Virtual Appliance versions 19.13.0.0 and prior. The flaw is an Improper Restriction of Excessive Authentication Attempts weakness [CWE-307] in the appliance's authentication interface. An unauthenticated remote attacker can repeatedly submit credentials without rate limiting or lockout enforcement. Successful exploitation can lead to unauthorized access to the appliance through credential brute forcing or password spraying.

Dell published advisory DSA-2025-387 to address this issue alongside other vulnerabilities in the same product line.

Critical Impact

Unauthenticated attackers with network access can brute force authentication on Dell CloudBoost Virtual Appliance, potentially gaining unauthorized access to the backup infrastructure component.

Affected Products

• Dell CloudBoost Virtual Appliance version 19.13.0.0
• Dell CloudBoost Virtual Appliance versions prior to 19.13.0.0
• Deployments integrating CloudBoost with Dell data protection backup workflows

Discovery Timeline

• 2025-12-05 - CVE-2025-46603 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2025-46603

Vulnerability Analysis

Dell CloudBoost Virtual Appliance is a backup acceleration component used with Dell data protection products to move deduplicated backup data to cloud object storage. The authentication interface on the appliance does not enforce limits on the number of failed authentication attempts originating from a single source.

Without account lockout, exponential back-off, or other throttling, an attacker can iterate through password dictionaries against valid usernames. Because the attack vector is the network and no privileges or user interaction are required, an attacker positioned to reach the appliance management interface can sustain a brute force campaign until valid credentials are recovered.

The impact is limited to confidentiality. A successful attacker gains access using legitimate credentials, which then provides a foothold into backup management workflows handled by CloudBoost.

Root Cause

The root cause is a missing or inadequate authentication throttling control [CWE-307]. The appliance accepts an unbounded number of authentication attempts from the same client or against the same account. There is no enforced delay, account lockout threshold, or CAPTCHA challenge that would slow automated credential guessing.

Attack Vector

The vulnerability is exploitable over the network without authentication or user interaction. An attacker submits crafted authentication requests to the CloudBoost management interface and iterates credentials using standard brute force or password spraying tooling. The vulnerability itself does not modify data or cause service disruption, but the access it enables can be leveraged for follow-on activity against backup infrastructure.

No public proof-of-concept exploit is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS probability is low at the time of publication.

Detection Methods for CVE-2025-46603

Indicators of Compromise

• High volumes of failed authentication events targeting the CloudBoost management interface from a single source or a small set of sources
• Authentication attempts against multiple accounts in rapid succession from one source address (password spraying pattern)
• Successful logins immediately following sustained failed attempts against the same account
• Logins from unexpected geographies or networks to CloudBoost administrative accounts

Detection Strategies

• Correlate appliance authentication logs to flag sources exceeding a tunable failure threshold within a short window
• Alert on a successful authentication that follows N consecutive failures for the same account
• Monitor for distributed brute force patterns where many sources each attempt a small number of credentials
• Track first-time-seen client IP addresses authenticating to CloudBoost management services

Monitoring Recommendations

• Forward CloudBoost authentication and access logs to a centralized SIEM or log platform for retention and correlation
• Baseline normal administrative authentication volume per account and alert on deviations
• Apply network access controls so that only known administrator subnets can reach the management interface, and alert on attempts from outside that scope

How to Mitigate CVE-2025-46603

Immediate Actions Required

• Apply the remediation provided in Dell advisory DSA-2025-387 to upgrade CloudBoost beyond version 19.13.0.0
• Restrict network reachability of the CloudBoost management interface to trusted administrative networks only
• Rotate credentials for any account that may have been exposed to brute force attempts prior to patching
• Review authentication logs for evidence of failed-attempt patterns since the appliance was deployed

Patch Information

Dell has released a fixed version of CloudBoost Virtual Appliance. Customers should consult the Dell Security Update DSA-2025-387 advisory for the corrected version and upgrade procedure. Apply the update on all CloudBoost instances at version 19.13.0.0 or earlier.

Workarounds

• Place the CloudBoost management interface behind a VPN or jump host to prevent direct network reachability from untrusted networks
• Enforce strong, unique passwords on all CloudBoost accounts to increase the cost of brute force attacks while patching is scheduled
• Apply firewall rules or access control lists that limit source IPs permitted to reach the authentication endpoint
• Increase log retention and review cadence for CloudBoost authentication events until the patch is deployed