---
title: "CVE-2026-28198: NetBackup Flex OS - Authentication Bypass"
description: "NetBackup Flex OS contains a broken authentication vulnerability caused by bypassing cryptographic signature verification in privileged support commands, letting authenticated low-privileged users gain unrestricted root shell access, exploit requires authenticated low-privileged user access to management shell."
url: https://panop.io/threat-heartbeat/CVE-2026-28198/
---

# CVE-2026-28198 NetBackup Flex OS - Authentication Bypass

NetBackup Flex OS contains a broken authentication vulnerability caused by bypassing cryptographic signature verification in privileged support commands, letting authenticated low-privileged users gain unrestricted root shell access, exploit requires authenticated low-privileged user access to management shell.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.34% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-28198)

## Details

Type

Authentication Bypass

Impact

Remote Code Execution, Privilege Escalation

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Published

18 September 2026

Updated

15 October 2026

Weakness

[CWE-347](https://cwe.mitre.org/data/definitions/347.html)

## Vendor fix

Update to the latest version with the cryptographic signature verification fix.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-28198](https://nvd.nist.gov/vuln/detail/CVE-2026-28198)
- [https://github.com/cohesity/SecAdvisory/blob/master/COH-2026-0001.md](https://github.com/cohesity/SecAdvisory/blob/master/COH-2026-0001.md)
- [https://www.cvcn.gov.it/cvcn/cve/CVE-2026-28198](https://www.cvcn.gov.it/cvcn/cve/CVE-2026-28198)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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