CVE-2026-5426

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

CVSS 9.1 CRITICALEPSS 1.0%CWE-321 CWE-502

Vexday Risk Score

48Attention

SSVC decision (CISA)

Attend

PoC available → attend closely

CVSS 9.1EPSS 1.0%KEV nãoPoC públicaNuclei —Metasploit —Patch —

Lifecycle

16 Apr 2026Published on NVD

26 May 2026Public PoC

Recommendation: Plan a near-term fix — a public PoC already exists.

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

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

Affected products

Digital Knowledge · KnowledgeDeliver

public PoCs found — 1

githubgithub.com/HORKimhab/CVE-2026-5426★ 0

⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.

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References

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