Vulnerability in Cohesity Netbackup Flex OS

CVE-2026-28198

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (27.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 27.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-28198: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-28198?
CVE-2026-28198 is a high-severity vulnerability in Cohesity Netbackup Flex OS, classified under Improper Verification of Cryptographic Signature. CVSS score: 8.8/10. Published 2026-09-18.
How severe is CVE-2026-28198?
High severity. CVSS v3 base score is 8.8 out of 10.