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CVE-2026-5426

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

Basic Information

CVE State: PUBLISHED
Reserved Date: April 02, 2026
Published Date: April 16, 2026
Last Updated: May 27, 2026
Vendor: Digital Knowledge
Product: KnowledgeDeliver
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

CVSS Scores

CVSS v3.1

9.1 - CRITICAL

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

SSVC Information

Exploitation: none
Automatable: Yes
Technical Impact: total

Exploit Status

Exploited in the Wild: Yes (2026-05-25 07:00:00 UTC) Source

References

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

Known Exploited Vulnerability Information

Source	Added Date
The Shadowserver (via CIRCL)	2026-05-25 07:00:00 UTC

Recent Mentions

KnowledgeDeliver LMS Flaw Exploited to Deploy Godzilla and Cobalt Strike

Source: TheHackerNews • Published: 2026-05-26 05:19:38 UTC

A now-patched high-severity security flaw affecting Digital Knowledge KnowledgeDeliver, a Learning Management System (LMS) popular in Japan, was exploited as a zero-day to deliver the Godzilla web shell and ultimately facilitate the deployment of Cobalt Strike Beacon. The vulnerability, tracked as CVE-2026-5426 (CVSS score: 7.5), stems from the use of hard-coded ASP.NET machine keys, leading to

Timeline

CVE ID Reserved

April 02, 2026
CVE Published to Public

April 16, 2026
Added to KEVIntel

May 25, 2026