CVE-2025-57789: Commvault Authentication Bypass Vulnerability

CVE-2025-57789 Overview

CVE-2025-57789 is a default credentials vulnerability [CWE-257] in Commvault. During the brief window between installation and the first administrator login, remote attackers can use the default credential to gain administrative control. The exposure is limited to the setup phase, before any jobs have been configured. Commvault addressed the issue in security advisory CV_2025_08_4.

Critical Impact
Remote attackers who reach a freshly installed Commvault instance before the first administrator login can authenticate with the default credential and take over the administrative interface.

Affected Products

Commvault (see vendor advisory for affected version ranges)
Deployments in the post-install, pre-first-login state
Network-reachable Commvault management interfaces

Discovery Timeline

2025-08-20 - CVE-2025-57789 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-57789

Vulnerability Analysis

The vulnerability stems from Commvault shipping with a default administrator credential that remains valid until the first administrator login completes. During this setup window, any network-reachable client can authenticate as administrator using the known default. The attacker does not need prior access, social engineering, or a separate exploit chain.

The exposure window is narrow but predictable. Automated installation pipelines, imaging, and unattended provisioning can leave systems in the pre-first-login state for extended periods. Backup platforms are high-value targets because they hold credentials, retain sensitive data copies, and can be abused for destructive actions or ransomware staging.

Root Cause

The root cause is the use of a hardcoded default credential [CWE-257] that is active before the operator establishes a unique administrator password. The application does not force credential rotation or block remote authentication until initial configuration is complete.

Attack Vector

Exploitation requires network access to the Commvault administrative interface during the setup phase. The attacker submits the known default credential and obtains an authenticated administrator session. No user interaction on the target side is required. After first login by a legitimate administrator, the default credential becomes unusable and this specific path closes.

No public proof-of-concept or exploit code is listed for CVE-2025-57789, and the vulnerability is not on the CISA Known Exploited Vulnerabilities catalog. Refer to the Commvault Security Advisory CV_2025_08_4 for vendor technical details.

Detection Methods for CVE-2025-57789

Indicators of Compromise

Successful administrator authentication events from unexpected source addresses shortly after a Commvault installation
Configuration changes, new user accounts, or role modifications occurring before the documented first-login handoff
Backup jobs, restore targets, or credential vault entries created immediately after install by an unknown operator
Outbound connections from the Commvault host to unfamiliar destinations during the initial provisioning window

Detection Strategies

Alert on any administrator login to a Commvault instance whose provisioning ticket is still open
Correlate Commvault audit logs with change-management records to flag configuration edits without an approved change
Baseline the expected source addresses for initial administrator access and flag deviations

Monitoring Recommendations

Forward Commvault authentication and audit logs to a central SIEM for retention and correlation
Track the time between service start and first administrator login for every new deployment
Monitor network telemetry for exposure of the Commvault management interface to untrusted networks

How to Mitigate CVE-2025-57789

Immediate Actions Required

Apply the fixes referenced in Commvault Security Advisory CV_2025_08_4
Rotate the administrator credential immediately after installation and before exposing the instance to any network segment
Audit recently deployed Commvault instances for unauthorized administrator logins or configuration changes
Restrict network reachability of the Commvault management interface to administrative subnets only

Patch Information

Commvault has published guidance and fixed builds in advisory CV_2025_08_4. Review the advisory for the exact fixed versions and apply the vendor-recommended update path. Confirm that new installations no longer accept the default credential after the update.

Workarounds

Perform installation on an isolated network segment and complete the first administrator login before connecting the host to production networks
Enforce host-based firewall rules that block inbound access to the management interface until provisioning is complete
Automate first-login and credential rotation as part of the installation pipeline to eliminate the exposure window

bash

# Configuration example: restrict management interface during provisioning
# Replace <MGMT_PORT> and <ADMIN_SUBNET> with your environment values
iptables -A INPUT -p tcp --dport <MGMT_PORT> -s <ADMIN_SUBNET> -j ACCEPT
iptables -A INPUT -p tcp --dport <MGMT_PORT> -j DROP