Detections
Analytics

CVE-2026-5426

critical

Description

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

References

https://www.securityweek.com/hackers-exploited-knowledgedeliver-zero-day-for-web-shell-deployment/

https://www.bleepingcomputer.com/news/security/knowledgedeliver-flaw-exploited-as-a-zero-day-to-install-web-shells/

https://thehackernews.com/2026/05/knowledgedeliver-lms-flaw-exploited-to.html

https://cloud.google.com/blog/topics/threat-intelligence/knowledgedeliver-viewstate-deserialization-vulnerability/

https://github.com/HORKimhab/CVE-2026-5426

https://www.digital-knowledge.co.jp/product/kd/

https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2026/MNDT-2026-0009.md

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-23271

https://cloud.google.com/blog/topics/threat-intelligence/knowledgedeliver-viewstate-deserialization-vulnerability

Details

Source: Mitre, NVD

Published: 2026-04-16

Updated: 2026-05-26

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 9.1

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

Severity: Critical

EPSS

EPSS: 0.00809