Commvault Cloud: Denial of service in MediaAgent via heap-based buffer overflow
Summary
A heap-based buffer overflow in MediaAgent of Commvault Cloud can be triggered over the network without authentication or user interaction. Successful exploitation can crash the service, which affects availability only and does not expose data or allow changes. Backup and restore operations may fail at the moment they are needed, for example after a ransomware incident.
Affected
- Commvault Cloud 11.46.0 to 11.46.29
- Commvault Cloud 11.44.0 to 11.44.24
- Commvault Cloud 11.40.0 to 11.40.77
- Commvault Cloud 11.36.0 to 11.36.126
- Components: MediaAgent and HyperScale (per CNA record)
- Default configuration: unknown
Fixed in
- Fixed in 11.46.30 (first changed version per CNA data; to be confirmed in the vendor advisory)
- Maintenance releases listed for other branches: 11.44.25, 11.40.78, 11.36.127 (October 6, 2026; not confirmed as the fix for this CVE)
- Latest 11.46 release listed: 11.46.40 (October 15, 2026)
Workaround
Unknown. No vendor workaround identified; the vendor advises upgrading.
- Restrict network access to MediaAgent and HyperScale to the backup network and administrators (own recommendation, not from the vendor).
Exploitation
- Not listed in the CISA KEV catalog.
- CISA SSVC: exploitation none, automatable yes, technical impact partial.
- No public proof of concept or vendor report of in-the-wild exploitation found in the research.
- EPSS: 0.00316 (very low).
Our recommendation
- Inventory all Commvault installations and versions, including MediaAgent and HyperScale.
- Compare versions with the affected ranges and check the vendor advisory CV_2026_10_6 for the exact fixed versions.
- Upgrade to the latest maintenance release on each branch, and update all Commvault installations, not only the affected component.
- Confirm that backup components are not reachable from the internet.
- Monitor for MediaAgent service crashes until patched.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Commvault Security Advisory CV_2026_10_6 documentation.commvault.com
- Commvault release types and release tracks documentation.commvault.com
- Commvault 11.40.78 release notes documentation.commvault.com
- Strix CVE-2026-77100 www.strix.ai
- Vulners CVE-2026-77100 vulners.com
- CyStack Commvault Cloud vulnerabilities cystack.net
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 04:26.
Original description (NVD)
MediaAgent contained a heap-based buffer overflow issue affecting service availability. Software customers upgrade to resolved maintenance release. Update Commvault installation of MediaAgents and HyperScale.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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