Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:N) | Network: reachable remotely |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:N) | No attack requirements |
| Privileges required (PR:N) | No privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:N) | No integrity impact |
| Availability (VA:N) | No availability impact |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
About Commvault
CVE-2026-77103 affects Commvault, a product from Commvault. Before acting, confirm where Commvault runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: CommServe contained an authentication bypass issue affecting access authorization and information disclosure. Software customers upgrade to resolved maintenance release. Update CommServe.
The weakness class is Authentication Bypass via Alternate Path. A second route into the app skips the login check.
Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Commvault |
| Affected versions | Commvault from 11.36.0 before 11.36.123; Commvault from 11.40.0 before 11.40.72; Commvault from 11.44.0 before 11.44.20; Commvault from 11.46.0 before 11.46.20 |
| Published | Sep 8, 2026 |
| Last modified | Sep 9, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | 050066fd-a2f9-4f32-ab5d-4c53f48bc333 |
How to detect it
- Inventory every instance of Commvault and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Commvault named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Commvault to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-288: Authentication Bypass via Alternate Path More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
Cvlaunchd contained a missing authorization issue affecting command execution authorization. Software customers upgrade to resolved maintenance release. Update all Commvault installations, including Commserve, Webserver, Command Center, Media Agents, Clients and HyperScale X.
CommServe contained a cryptographic signature verification issue affecting privilege management. Software customers upgrade to resolved maintenance release. Update CommServe and Web Server.
CommServe contained a path traversal issue affecting information disclosure. Software customers upgrade to resolved maintenance release. Update CommServe.
CommServe contained a heap-based buffer overflow issue affecting service availability. Software customers upgrade to resolved maintenance release. Update CommServe.
CommServe contained a stack-based buffer overflow issue affecting service availability. Software customers upgrade to resolved maintenance release. Update CommServe.
Private Metrics Server contained an SQL injection condition affecting database operations. Software customers upgrade to resolved maintenance release. Update Private Metrics Server.
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