Vulnerability-Lookup

CVE-2026-5426 (GCVE-0-2026-5426)

Vulnerability from cvelistv5 – Published: 2026-04-16 15:18 – Updated: 2026-05-27 14:53

Previdian

Title

KnowledgeDeliver deployments before February 24, 2026 use a static ASP.NET/IIS machineKey value

Summary

Hard-coded ASP.NET/IIS machineKey value in Digital Knowledge KnowledgeDeliver deployments prior to February 24, 2026 allows adversaries to circumvent ViewState validation mechanisms and achieve remote code execution via malicious ViewState deserialization attacks

Severity

9.1 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-26 17:08 UTC

CWE

CWE-321 - Use of hard-coded cryptographic key
CWE-502 - Deserialization of untrusted data

Assigner

Mandiant CNA under the Google root

CNA scorecard B 80/100 over 14 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/mandiant/Vulnerability-Disclos…	third-party-advisory
https://www.digital-knowledge.co.jp/product/kd/	product
https://cloud.google.com/blog/topics/threat-intel…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
Digital Knowledge	KnowledgeDeliver	Affected: 0 , < 20260224 (date)	guessed

Previdian

Known Exploited Vulnerability - GCVE BCP-07 Compliant

KEV entry ID: 66c1e780-c52f-45be-934f-204367b04f1e

Vulnerability ID: CVE-2026-5426

Status: Confirmed

Status Updated: 2026-05-25 07:00 UTC

Exploited: Yes

Timestamps

First Seen: 2026-05-25

Asserted: 2026-05-25

Scope

Notes: KEVIntel entry: KnowledgeDeliver deployments before February 24, 2026 use a static ASP.NET/IIS machineKey value | Affected: Digital Knowledge / KnowledgeDeliver | CVSS: 9.1 (CRITICAL) | EPSS: 0.0081 | Used in malware: unknown | Not yet in CISA KEV: True

Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: kevintel

Details

Feed	KEVIntel (kevintel.com)
Title	KnowledgeDeliver deployments before February 24, 2026 use a static ASP.NET/IIS machineKey value
Vendor	Digital Knowledge
Product	KnowledgeDeliver
Added Date	2026-05-25T07:00:00.000Z
Cvss Score	9.1
Epss Score	0.0081
Cvss Severity	CRITICAL
Epss Percentile	0.52104
Used In Malware	unknown
Ahead Of Cisa Kev	None
Not Yet In Cisa Kev	True

References

Created: 2026-06-19 12:42 UTC | Updated: 2026-06-19 12:42 UTC

Show details on NVD website

JSON

To clipboard

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}

FKIE_CVE-2026-5426

Vulnerability from fkie_nvd - Published: 2026-04-16 16:16 - Updated: 2026-06-17 10:59

Previdian

Severity

9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Summary

References

	URL	Tags
	mandiant-cve@google.com	https://cloud.google.com/blog/topics/threat-intelligence/knowledgedeliver-viewstate-deserialization-vulnerability
	mandiant-cve@google.com	https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2026/MNDT-2026-0009.md
	mandiant-cve@google.com	https://www.digital-knowledge.co.jp/product/kd/

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "KnowledgeDeliver",
          "vendor": "Digital Knowledge",
          "versions": [
            {
              "lessThan": "20260224",
              "status": "affected",
              "version": "0",
              "versionType": "date"
            }
          ]
        }
      ],
      "source": "mandiant-cve@google.com"
    }
  ],
  "cveTags": [],
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      "lang": "en",
      "value": "Hard-coded ASP.NET/IIS machineKey value in Digital Knowledge KnowledgeDeliver deployments prior to February 24, 2026 allows adversaries to circumvent ViewState validation mechanisms and achieve remote code execution via malicious ViewState deserialization attacks"
    }
  ],
  "id": "CVE-2026-5426",
  "lastModified": "2026-06-17T10:59:00.653",
  "metrics": {
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      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.1,
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          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
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        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
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    ],
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      "source": "mandiant-cve@google.com",
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    },
    {
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      "url": "https://www.digital-knowledge.co.jp/product/kd/"
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}

GHSA-G88C-8GFJ-6C98

Vulnerability from github – Published: 2026-04-16 18:31 – Updated: 2026-05-26 21:31

Details

Severity

7.5 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-5426"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-321"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-16T16:16:17Z",
    "severity": "HIGH"
  },
  "details": "Hard-coded ASP.NET/IIS machineKey value in Digital Knowledge KnowledgeDeliver deployments prior to February 24, 2026 allows adversaries to circumvent ViewState validation mechanisms and achieve remote code execution via malicious ViewState deserialization attacks",
  "id": "GHSA-g88c-8gfj-6c98",
  "modified": "2026-05-26T21:31:37Z",
  "published": "2026-04-16T18:31:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5426"
    },
    {
      "type": "WEB",
      "url": "https://cloud.google.com/blog/topics/threat-intelligence/knowledgedeliver-viewstate-deserialization-vulnerability"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2026/MNDT-2026-0009.md"
    },
    {
      "type": "WEB",
      "url": "https://www.digital-knowledge.co.jp/product/kd"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

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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.

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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.

Action not permitted

CVE-2026-5426 (GCVE-0-2026-5426)

Previdian

Known Exploited Vulnerability - GCVE BCP-07 Compliant

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Scope

Evidence

Public Report Successful Exploitation Confidence: 70% Source: kevintel

Details

References

FKIE_CVE-2026-5426

GHSA-G88C-8GFJ-6C98

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Related by attack behaviour