CVE-2021-34993: Authentication Bypass in Commvault CommCell

The impact of CVE-2021-34993 is severe due to the ease of exploitation and the potential for widespread compromise. An attacker can leverage this vulnerability to gain unauthorized access to CommCell environments without needing valid credentials. This could lead to data breaches, data manipulation, system disruption, and potentially lateral movement within the network. Successful exploitation could allow an attacker to access sensitive data stored and managed by CommCell, including backups and recovery information. The lack of authentication requirements significantly lowers the barrier to entry for malicious actors.

1. Reserved2021-06-17
2. Published2022-01-13
3. Modified2024-08-04
4. EPSS updated2026-04-02

The primary mitigation for CVE-2021-34993 is to upgrade Commvault CommCell to a patched version. Refer to the Commvault advisory for the specific fixed version. If immediate patching is not possible due to compatibility concerns or testing requirements, consider implementing network segmentation to restrict access to the CommCell server. Review and strengthen existing access controls and monitoring to detect any suspicious activity. While a WAF cannot directly prevent this authentication bypass, it can help detect and block malicious requests targeting the vulnerable endpoint. After upgrading, verify the fix by attempting to access the CVSearchService without providing valid credentials; access should be denied.