CVE-2026-77094 in Commvault
Summary
by MITRE • 10/13/2026
CvFWD contained an out-of-bounds write affecting service availability. Software customers upgrade to resolved maintenance release. Software customers upgrade to resolved maintenance release. Update all Commvault installations, including CommServe, Webserver, Command Center, MediaAgents, Clients and HyperScale.
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Analysis
by VulDB Data Team • 10/13/2026
The vulnerability identified in CvFWD represents a critical out-of-bounds write condition that directly compromises the availability of the affected service within the Commvault ecosystem. Out-of-bounds writes are among the most severe memory corruption vulnerabilities because they allow an attacker to overwrite adjacent memory locations with arbitrary data, potentially leading to application crashes, denial of service, or more sophisticated exploitation chains such as code execution. In this specific instance, the primary observed impact is on service availability, indicating that the flaw likely causes a segmentation fault or similar fatal error when triggered by malformed input or unexpected state transitions within the CvFWD component. This aligns with CWE-787, which classifies out-of-bounds write as a memory corruption vulnerability where data is written to a location outside the intended buffer boundary, often resulting in system instability and service interruption.
The operational impact of this flaw extends beyond simple application crashes. Since CvFWD appears to be an integral component within the Commvault architecture, its failure can disrupt critical backup and recovery operations. Customers relying on continuous availability for their data protection strategies may experience significant downtime if the vulnerability is triggered in a production environment. The instability introduced by the out-of-bounds write could also mask other underlying issues or create conditions that facilitate further exploitation attempts against related services such as CommServe, Webserver, Command Center, MediaAgents, Clients, and HyperScale nodes. This highlights the importance of maintaining strict memory safety standards across all distributed components to ensure holistic system resilience.
From a threat modeling perspective, this vulnerability can be mapped to ATT&CK technique T1499, Endpoint Denial of Service, specifically under sub-techniques involving resource exhaustion or application crash exploitation. While the immediate effect is denial of service, memory corruption vulnerabilities like CWE-787 are frequently leveraged as stepping stones for privilege escalation or remote code execution if additional conditions such as executable stack segments or lack of ASLR are present in the deployment environment. Therefore, treating this solely as an availability issue may underestimate its potential risk profile in a compromised network segment where lateral movement is attempted.
To mitigate this vulnerability and restore secure operations, it is imperative that all software customers upgrade to the resolved maintenance release provided by Commvault. The remediation strategy must be comprehensive across the entire infrastructure footprint. This includes updating every instance of CommServe, which acts as the central management console; Webserver components handling user interfaces; Command Center instances for cloud-based administration; MediaAgents responsible for data transfer and storage operations; Clients that initiate backup jobs; and HyperScale nodes forming the scalable storage fabric. Failure to update any single component may leave a persistent attack vector within the environment, potentially allowing an adversary to target less protected segments of the architecture. Regular patch management cycles aligned with vendor advisories are essential to maintain the integrity and availability of enterprise data protection systems against known memory corruption flaws.