Deserialization in Digital Knowledge Knowledgedeliver
CVE-2026-5426
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
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.008 (55.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.010 · newest: 0.008 · change: -0.002
Affected products
- Digital Knowledge Knowledgedeliver — versions 0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/mandiant/Vulnerability-Disclosures/blob/master/2026/MNDT-2026-0009.md (third-party-advisory)
- www.digital-knowledge.co.jp/product/kd/ (product)
- cloud.google.com/blog/topics/threat-intelligence/knowledgedeliver-viewstate-des… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-5426?
- CVE-2026-5426 is a critical-severity vulnerability in Digital Knowledge Knowledgedeliver, classified under Use of Hard-coded Cryptographic Key. CVSS score: 9.1/10. Published 2026-04-16.
- How severe is CVE-2026-5426?
- Critical severity. CVSS v3 base score is 9.1 out of 10.
- Is CVE-2026-5426 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.