Vulnerability-Lookup

CVE-2026-28198 (GCVE-0-2026-28198)

Vulnerability from cvelistv5 – Published: 2026-09-18 11:12 – Updated: 2026-09-18 14:31

Title

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

Summary

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.

Severity

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

8.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-18 14:14 UTC

CWE

CWE-347 - Improper verification of cryptographic signature

Assigner

ENISA ENISA root

References

2 references

URL	Tags
https://www.cvcn.gov.it/cvcn/cve/CVE-2026-28198	government-resource
https://github.com/cohesity/SecAdvisory/blob/mast…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
Cohesity	NetBackup Flex OS	Affected: 0 , < 6.4 (custom)	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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                "id": "CVE-2026-28198",
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          }
        ],
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                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
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}

GHSA-H4HC-X5F6-WFC4

Vulnerability from github – Published: 2026-09-18 12:31 – Updated: 2026-09-18 12:31

Details

Severity

8.8 (High)


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

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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-28198"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-18T12:17:24Z",
    "severity": "CRITICAL"
  },
  "details": "An authenticated, low-privileged user with access to the NetBackup Flex \nOS management shell could bypass the cryptographic signature \nverification step of a privileged support command by supplying a \nspecially formed access credential. Successful exploitation grants the \nattacker an unrestricted root shell with full control over the Flex \nappliance host and all hosted containers, completely compromising \nconfidentiality, integrity, and availability.",
  "id": "GHSA-h4hc-x5f6-wfc4",
  "modified": "2026-09-18T12:31:20Z",
  "published": "2026-09-18T12:31:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28198"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cohesity/SecAdvisory/blob/master/COH-2026-0001.md"
    },
    {
      "type": "WEB",
      "url": "https://www.cvcn.gov.it/cvcn/cve/CVE-2026-28198"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.