CVE-2026-5426

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 1.0%, top 41% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
9.1
EG Score
9.1(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
59.4%
KEV
Not listed

Published

April 16, 2026

Last Modified

May 26, 2026

Advisory Details (3)

Auto-updated May 31, 2026
No patch confirmed yet.
generic

KnowledgeDeliver(LMS) | eラーニングのデジタル・ナレッジ

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

Vulnerability-Disclosures/2026/MNDT-2026-0009.md at master · mandiant/Vulnerability-Disclosures · GitHub

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

Exploitation of KnowledgeDeliver via ViewState Deserialization Vulnerability | Google Cloud Blog

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

Vendor Advisories for CVE-2026-5426(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 110 total refreshes for this CVE.

  1. 2026-07-23 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:19 UTCEG score recompute▲ 1.60
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-22 14:08 UTCEPSS rescore
  6. 2026-07-21 15:25 UTCEPSS rescore
  7. 2026-07-21 15:25 UTCEPSS rescore
  8. 2026-07-20 17:08 UTCEPSS rescore
  9. 2026-07-19 14:31 UTCEPSS rescore
  10. 2026-07-19 02:29 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-16 17:03 UTCEPSS rescore
  13. 2026-07-15 16:57 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-15 02:00 UTCEPSS rescore
  16. 2026-07-15 02:00 UTCEPSS rescore
  17. 2026-07-13 22:31 UTCEPSS rescore
  18. 2026-07-13 06:13 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-11 08:27 UTCEPSS rescore
  23. 2026-07-09 19:10 UTCEPSS rescore
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-08 15:16 UTCEPSS rescore
Show 75 more
  1. 2026-07-08 15:16 UTCEPSS rescore
  2. 2026-07-07 13:46 UTCEPSS rescore
  3. 2026-07-07 13:46 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 02:23 UTCEPSS rescore
  7. 2026-07-06 02:23 UTCEPSS rescore
  8. 2026-07-05 02:31 UTCEPSS rescore
  9. 2026-07-05 02:30 UTCEPSS rescore
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-04 06:31 UTCEPSS rescore
  12. 2026-07-01 15:07 UTCEPSS rescore
  13. 2026-06-30 23:22 UTCEPSS rescore
  14. 2026-06-29 14:06 UTCEPSS rescore
  15. 2026-06-28 14:07 UTCEPSS rescore
  16. 2026-06-28 04:56 UTCEPSS rescore
  17. 2026-06-27 03:08 UTCEPSS rescore
  18. 2026-06-25 13:49 UTCEPSS rescore
  19. 2026-06-24 14:05 UTCEPSS rescore
  20. 2026-06-23 21:33 UTCEPSS rescore
  21. 2026-06-23 21:33 UTCEPSS rescore
  22. 2026-06-22 14:25 UTCEPSS rescore
  23. 2026-06-22 14:25 UTCEPSS rescore
  24. 2026-06-21 14:56 UTCEPSS rescore
  25. 2026-06-21 14:56 UTCEPSS rescore
  26. 2026-06-21 01:59 UTCEPSS rescore
  27. 2026-06-21 01:59 UTCEPSS rescore
  28. 2026-06-19 19:26 UTCEPSS rescore
  29. 2026-06-19 19:26 UTCEPSS rescore
  30. 2026-06-18 17:52 UTCEPSS rescore
  31. 2026-06-18 17:52 UTCEPSS rescore
  32. 2026-06-17 17:53 UTCEPSS rescore
  33. 2026-06-16 17:53 UTCEPSS rescore
  34. 2026-06-15 17:49 UTCEPSS rescore
  35. 2026-06-15 17:49 UTCEPSS rescore
  36. 2026-06-14 23:18 UTCEPSS rescore
  37. 2026-06-14 19:52 UTCGHSA enrichment
  38. 2026-06-13 23:00 UTCEPSS rescore
  39. 2026-06-12 23:12 UTCEPSS rescore
  40. 2026-06-12 23:12 UTCEPSS rescore
  41. 2026-06-12 07:50 UTCGHSA enrichment
  42. 2026-06-11 18:53 UTCGHSA enrichment
  43. 2026-06-11 14:00 UTCEPSS rescore
  44. 2026-06-10 22:19 UTCEPSS rescore
  45. 2026-06-10 13:22 UTCEPSS rescore
  46. 2026-06-10 12:38 UTCGHSA enrichment
  47. 2026-06-10 00:19 UTCGHSA enrichment
  48. 2026-06-09 10:02 UTCGHSA enrichment
  49. 2026-06-08 14:17 UTCEPSS rescore
  50. 2026-06-08 05:40 UTCGHSA enrichment
  51. 2026-06-07 17:21 UTCGHSA enrichment
  52. 2026-06-07 15:25 UTCEPSS rescore
  53. 2026-06-07 05:01 UTCGHSA enrichment
  54. 2026-06-06 13:47 UTCEPSS rescore
  55. 2026-06-06 08:56 UTCGHSA enrichment
  56. 2026-06-05 22:47 UTCEPSS rescore
  57. 2026-06-05 12:16 UTCGHSA enrichment
  58. 2026-06-05 06:10 UTCEPSS rescore
  59. 2026-06-05 06:10 UTCEPSS rescore
  60. 2026-06-04 21:04 UTCGHSA enrichment
  61. 2026-06-04 13:12 UTCEPSS rescore
  62. 2026-06-04 13:12 UTCEPSS rescore
  63. 2026-06-03 18:13 UTCGHSA enrichment
  64. 2026-06-02 20:13 UTCEPSS rescore
  65. 2026-06-02 14:05 UTCGHSA enrichment
  66. 2026-06-01 18:06 UTCGHSA enrichment
  67. 2026-06-01 13:52 UTCEPSS rescore
  68. 2026-06-01 13:52 UTCEPSS rescore
  69. 2026-05-31 22:30 UTCEPSS rescore
  70. 2026-05-31 22:30 UTCEPSS rescore
  71. 2026-05-31 00:16 UTCEPSS rescore
  72. 2026-05-31 00:16 UTCEPSS rescore
  73. 2026-05-29 13:44 UTCEPSS rescore
  74. 2026-05-29 13:44 UTCEPSS rescore
  75. 2026-05-28 13:44 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-5426?
CVE-2026-5426 is a critical vulnerability published on April 16, 2026. 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
When was CVE-2026-5426 disclosed?
CVE-2026-5426 was first published in the National Vulnerability Database on April 16, 2026, with the most recent update on May 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-5426 actively exploited?
CVE-2026-5426 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 59.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-5426?
CVE-2026-5426 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-5426?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-5426, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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