Commvault Issues Urgent Patch for Critical Webserver Vulnerability

Commvault Urgently Patches Critical Webserver Vulnerability Enabling Webshell Attacks​

Commvault, a global leader in enterprise data protection and management solutions, has issued an urgent patch for a high-severity vulnerability in its webserver component. This flaw, affecting multiple versions of Commvault’s software across both Linux and Windows platforms, could allow threat actors to inject and execute malicious webshells—granting persistent remote control over compromised systems.

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The Vulnerability Explained​

The vulnerability resides in the webserver layer of Commvault’s software stack. Due to improper input validation, attackers can craft HTTP requests that inject and execute arbitrary code. Specifically, the flaw enables the creation and execution of stealthy webshells—scripts normally written in ASP, PHP, or JSP—using compromised file upload mechanisms or injection techniques.
Key points include:

• Exploitation Mechanism:
  • Attackers send carefully crafted HTTP POST requests to vulnerable endpoints.
  • The vulnerability allows writing executable files to the webserver directory.
  • Once deployed, these webshells bypass authentication, manipulate sensitive data, and enable lateral movement within the network.
• Impact on Security:
  • Unauthorized access and data exfiltration.
  • Potential for systemic breaches across multiple environments.
  • The ability to remain stealthy and persistent, evading traditional endpoint detection systems.

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Affected Versions and Patch Deployment​

The flaw impacts all supported Commvault versions from 11.20 through 11.36. In response, Commvault initially rolled out patched releases on March 4, 2025, followed by additional fixes on March 7 to reinforce webserver security further. Organizations are urged to update both the CommServe and Web Server components promptly to mitigate the risk of exploitation.

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Mitigation and Recommended Actions​

Commvault has mandated immediate installation of the maintenance releases via its “Software Updates on Demand” utility. Security teams are advised to adopt the following measures:

• Patch Application:
  • Validate current software versions using the Get-CommVaultVersion PowerShell cmdlet.
  • Download patches from Commvault’s secured repository using TLS 1.2+ protocols.
  • Deploy updates during scheduled maintenance windows, ensuring compatibility with linked modules such as the CommCell Console and Content Store.
• Network Security Enhancements:
  • Enforce network segmentation and set strict inbound/outbound firewall rules for Commvault’s web ports (e.g., TCP/80, TCP/443).
  • Monitor audit logs for anomalous POST requests to /webconsole/API or unexpected creations of *.jspx files.
• Proactive Monitoring:
  • Scan networks for unpatched instances using version-check scripts.
  • Watch for indicators of compromise (IOCs), such as unexpected cmd.exe spawns or connections to suspicious IP addresses.
  • Review third-party integrations reliant on Commvault APIs (e.g., SAP HANA, Oracle DB) to ensure they are not exposed.

Failure to apply these patches promptly risks exploitation that could lead to catastrophic breaches similar to previous ransomware incidents leveraging vulnerabilities in other enterprise tools.

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The Broader Implications​

With Commvault software underpinning data protection systems in sectors such as finance, healthcare, and government, this vulnerability’s exploitation could have far-reaching consequences. As cybercriminals increasingly target backup systems to maximize the impact of their attacks, securing Commvault environments is critical to ensuring organizational resilience.
The recent patch underscores the ongoing threat landscape where even trusted enterprise solutions must constantly evolve their security posture in response to sophisticated adversaries.

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Final Thoughts​

The discovery and rapid patching of this webserver vulnerability serve as a stark reminder of the critical importance of robust input validation and regular update cycles in enterprise software. Organizations using Commvault must prioritize the immediate deployment of these updates and review their overall security strategy to protect against stealthy webshell-based attacks.
Staying vigilant, implementing layered security measures, and ensuring prompt patch management are essential steps in safeguarding vital data protection infrastructures against modern cyber threats.
For further details and to stay informed on the latest cybersecurity updates, visit the official Commvault advisories and trusted threat intelligence sources.

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Source: CybersecurityNews Commvault Webserver Vulnerability Let Attackers Compromise Webserver