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

published 2026-04-16 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-23271

cvss: 9.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.0%; EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits: 0; none known

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

Patch / fix

fixed in 1

Digital Knowledge KnowledgeDeliver 20260224

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 5 mo ago (2026-05-26)

Exploit prediction

1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CNA	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Digital Knowledge KnowledgeDeliver

Classification

Weakness

CWE-321 Use of Hard-coded Cryptographic Key
CWE-502 Deserialization of Untrusted Data

References

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

Sources

CVE List CVE-2026-5426
NVD CVE-2026-5426

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary