CVE-2026-28198

Privilege Escalation via Cryptographic Signature Verification Bypass in NetBackup Flex OS Shell

Published Sep 18, 2026 CVSS 4.0 · 9.4 Critical EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Workaround

Restrict management shell access to authorized administrators only. No compensating control fully eliminates the risk; upgrading is required.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Cohesity
Cohesity netbackup Flex Os
Vendors & Products Cohesity
Cohesity netbackup Flex Os
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Privilege Escalation via Cryptographic Signature Verification Bypass in NetBackup Flex OS Shell
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.4, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
ENISA
Published
Updated
Sep 18, 2026, 2:31 PM
Reserved
Feb 25, 2026, 2:02 PM
Status
Deferred
Published
Sep 18, 2026, 12:17 PM
Modified
Sep 18, 2026, 7:24 PM