CVE-2026-28198
Privilege Escalation via Cryptographic Signature Verification Bypass in NetBackup Flex OS Shell
An authenticated, low-privileged user with access to the NetBackup Flex OS management shell could bypass the cryptographic signature verification step of a privileged support command by supplying a specially formed access credential. Successful exploitation grants the attacker an unrestricted root shell with full control over the Flex appliance host and all hosted containers, completely compromising confidentiality, integrity, and availability.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Privilege Escalation via Cryptographic Signature Verification Bypass in NetBackup Flex OS Shell
An authenticated, low-privileged user with access to the NetBackup Flex OS management shell could bypass the cryptographic signature verification step of a privileged support command by supplying a specially formed access credential. Successful exploitation grants the attacker an unrestricted root shell with full control over the Flex appliance host and all hosted containers, completely compromising confidentiality, integrity, and availability.
- Record
CVE-2026-28198- CVSS 4.0
- 9.4 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-347
- Updated
- 2026-11-02
EUVDEUVD-2026-82875
An authenticated, low-privileged user with access to the NetBackup Flex OS management shell could bypass the cryptographic signature verification step of a privileged support command by supplying a specially formed access credential. Successful exploitation grants the attacker an unrestricted root shell with full control over the Flex appliance host and all hosted containers, completely compromising confidentiality, integrity, and availability.
- Record
EUVD-2026-82875- CVSS 4.0
- 9.4 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-h4hc-x5f6-wfc4
An authenticated, low-privileged user with access to the NetBackup Flex OS management shell...
An authenticated, low-privileged user with access to the NetBackup Flex OS management shell could bypass the cryptographic signature verification step of a privileged support command by supplying a specially formed access credential. Successful exploitation grants the attacker an unrestricted root shell with full control over the Flex appliance host and all hosted containers, completely compromising confidentiality, integrity, and availability.
- Record
GHSA-h4hc-x5f6-wfc4- CVSS 4.0
- 9.4 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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 - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-347
- Updated
- 2026-11-02
NVD
An authenticated, low-privileged user with access to the NetBackup Flex OS management shell could bypass the cryptographic signature verification step of a privileged support command by supplying a specially formed access credential. Successful exploitation grants the attacker an unrestricted root shell with full control over the Flex appliance host and all hosted containers, completely compromising confidentiality, integrity, and availability.
- Record
CVE-2026-28198- CVSS 4.0
- 9.4 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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 - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-347
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-28198 is a critical vulnerability (CVSS 9.4) in Cohesity Netbackup Flex Os, published September 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 27th percentile. No source names a fixed version.