CVE-2026-77089: Commvault Command Center Auth Bypass Flaw

CVE-2026-77089 Overview

CVE-2026-77089 is an authentication bypass vulnerability in the Commvault Command Center API. The flaw affects privilege management, allowing unauthenticated network-based attackers to bypass authentication controls. Commvault has released maintenance updates to resolve the issue and instructs software customers to upgrade Command Center. The vulnerability is tracked under CWE-290: Authentication Bypass by Spoofing.

Critical Impact
Remote attackers can bypass authentication in the Command Center API and interact with privilege management functions without valid credentials, threatening the confidentiality, integrity, and availability of the Commvault environment.

Affected Products

Commvault Commvault (Command Center API)
On-premises Commvault software deployments prior to the resolved maintenance release
Environments exposing the Command Center API over the network

Discovery Timeline

2026-09-08 - CVE-2026-77089 published to the National Vulnerability Database
2026-09-11 - Last updated in NVD database

Technical Details for CVE-2026-77089

Vulnerability Analysis

The Commvault Command Center API contains an authentication bypass affecting privilege management workflows. An attacker reaches the API over the network without prior credentials, user interaction, or elevated privileges. Because privilege management is the affected surface, a successful bypass can be leveraged to manipulate access decisions inside the Command Center. The vulnerability is classified under CWE-290, which covers authentication bypass through spoofed identity or trust assertions. Commvault addressed the issue in a maintenance release referenced in the Commvault Security Advisory CV_2026_07_1.

Root Cause

The underlying issue is improper enforcement of authentication on API endpoints that govern privilege management. Under CWE-290, the API accepts requests as trusted without validating the caller's identity through the intended authentication mechanism. This allows a request originating from an unauthenticated network client to be treated as if it belonged to a legitimate user or role.

Attack Vector

Exploitation occurs over the network against a reachable Command Center API endpoint. No credentials, no user interaction, and no privileges are required. An attacker sends crafted API requests targeting privilege management functionality and receives responses as though authenticated. Verified technical exploitation details have not been published; refer to the Commvault Security Advisory CV_2026_07_1 for authoritative guidance.

No public proof-of-concept exploit code has been released for CVE-2026-77089 at the time of publication. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-77089

Indicators of Compromise

Unexpected API requests to Command Center privilege management endpoints from unfamiliar source addresses.
Privilege changes, role assignments, or account modifications with no corresponding authenticated administrator session.
Authentication or audit log entries that reference actions without a preceding successful login event.
Access from geographies or networks that do not match the organization's administrative baseline.

Detection Strategies

Review Commvault Command Center audit logs for privilege management activity that cannot be tied to an authenticated administrator.
Correlate web server and reverse proxy logs for unauthenticated requests reaching Command Center API paths.
Alert on new or modified Commvault users, roles, and permissions occurring outside of change windows.
Compare current administrative role assignments against a known-good baseline on a scheduled cadence.

Monitoring Recommendations

Forward Commvault Command Center logs to a central SIEM or data lake for retention and correlation.
Monitor for anomalous request volume or error patterns against the Command Center API.
Track outbound network activity from Commvault servers for signs of post-exploitation behavior.
Enable alerting on modifications to backup, restore, and retention policies that could indicate abuse.

How to Mitigate CVE-2026-77089

Immediate Actions Required

Upgrade Commvault Command Center to the resolved maintenance release identified in Commvault Security Advisory CV_2026_07_1.
Restrict network exposure of the Command Center API to trusted administrative networks only.
Audit administrative users, roles, and recent privilege management changes for unauthorized activity.
Rotate credentials and API tokens for accounts that interact with Command Center if compromise is suspected.

Patch Information

Commvault has released a maintenance update that resolves CVE-2026-77089. Administrators should apply the fixed release referenced in Commvault Security Advisory CV_2026_07_1. Follow Commvault's documented upgrade procedures for Command Center and validate the environment after patching.

Workarounds

Place the Command Center behind a VPN or bastion host to remove direct internet exposure.
Enforce network-layer access control lists that restrict API access to a defined administrative subnet.
Require multi-factor authentication for all administrative access paths to Commvault infrastructure.
Increase audit log retention and monitoring until the maintenance release is fully deployed.

bash

# Configuration example: restrict Command Center API exposure at the network edge
# Example iptables rules limiting inbound access to a trusted admin subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.20.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP