CVE-2026-40097

LOWNVD 3.73.7—
EchelonGraph scoreMEDIUM confidence

This low-severity CVE scores 3.7 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 83% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
3.7
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 3.7Exploit: NoneExposed: 0

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

Step CA is an online certificate authority for secure, automated certificate management for DevOps. From 0.24.0 to before 0.30.0-rc3, an attacker can trigger an index out-of-bounds panic in Step CA by sending a crafted attestation key (AK) certificate with an empty Extended Key Usage (EKU) extension during TPM device attestation. When processing a device-attest-01 ACME challenge using TPM attestation, Step CA validates that the AK certificate contains the tcg-kp-AIKCertificate Extended Key Usage OID. During this validation, the EKU extension value is decoded from its ASN.1 representation and the first element is checked. A crafted certificate could include an EKU extension that decodes to an empty sequence, causing the code to panic when accessing the first element of the empty slice. This vulnerability is only reachable when a device-attest-01 ACME challenge with TPM attestation is configured. Deployments not using TPM device attestation are not affected. This vulnerability is fixed in 0.30.0-rc3.

CVSS v3
3.7
EG Score
3.7(medium)
EPSS
7.8%
KEV
Not listed

Published

April 10, 2026

Last Modified

April 27, 2026

References (4)

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/smallstep/certificates—0.30.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 34× 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.

  1. 2026-07-12 05:46 UTCEPSS rescore
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-09 19:10 UTCEPSS rescore
  4. 2026-07-08 15:15 UTCEPSS rescore
  5. 2026-07-07 13:46 UTCEPSS rescore
  6. 2026-07-06 16:27 UTCEPSS rescore
  7. 2026-07-06 16:27 UTCEPSS rescore
  8. 2026-07-06 02:23 UTCEPSS rescore
  9. 2026-07-06 02:23 UTCEPSS rescore
  10. 2026-07-05 02:30 UTCEPSS rescore
  11. 2026-07-04 06:31 UTCEPSS rescore
  12. 2026-07-01 15:06 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. 2026-06-25 13:49 UTCEPSS rescore
  20. 2026-06-24 14:05 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
Show 54 more
  1. 2026-06-21 01:59 UTCEPSS rescore
  2. 2026-06-19 19:25 UTCEPSS rescore
  3. 2026-06-17 17:53 UTCEPSS rescore
  4. 2026-06-16 17:52 UTCEPSS rescore
  5. 2026-06-15 17:49 UTCEPSS rescore
  6. 2026-06-15 04:19 UTCEG score recompute
  7. 2026-06-13 23:00 UTCEPSS rescore
  8. 2026-06-12 23:12 UTCEPSS rescore
  9. 2026-06-12 23:12 UTCEPSS rescore
  10. 2026-06-11 14:00 UTCEPSS rescore
  11. 2026-06-10 22:18 UTCEPSS rescore
  12. 2026-06-10 13:22 UTCEPSS rescore
  13. 2026-06-10 13:22 UTCEPSS rescore
  14. 2026-06-10 12:00 UTCEG score recompute
  15. 2026-06-08 14:17 UTCEPSS rescore
  16. 2026-06-08 14:17 UTCEPSS rescore
  17. 2026-06-07 15:25 UTCEPSS rescore
  18. 2026-06-07 15:25 UTCEPSS rescore
  19. 2026-06-07 07:58 UTCEG score recompute
  20. 2026-06-06 13:47 UTCEPSS rescore
  21. 2026-06-06 13:47 UTCEPSS rescore
  22. 2026-06-05 22:47 UTCEPSS rescore
  23. 2026-06-05 22:47 UTCEPSS rescore
  24. 2026-06-05 06:10 UTCEPSS rescore
  25. 2026-06-05 06:10 UTCEPSS rescore
  26. 2026-06-04 13:12 UTCEPSS rescore
  27. 2026-06-04 13:12 UTCEPSS rescore
  28. 2026-06-02 22:42 UTCEG score recompute
  29. 2026-06-02 20:13 UTCEPSS rescore
  30. 2026-06-01 13:52 UTCEPSS rescore
  31. 2026-06-01 13:52 UTCEPSS rescore
  32. 2026-06-01 13:51 UTCEPSS rescore
  33. 2026-05-31 22:30 UTCEPSS rescore
  34. 2026-05-31 22:30 UTCEPSS rescore
  35. 2026-05-31 00:16 UTCEPSS rescore
  36. 2026-05-31 00:16 UTCEPSS rescore
  37. 2026-05-31 00:16 UTCEPSS rescore
  38. 2026-05-29 13:44 UTCEPSS rescore
  39. 2026-05-29 13:44 UTCEPSS rescore
  40. 2026-05-28 13:44 UTCEPSS rescore
  41. 2026-05-28 13:44 UTCEPSS rescore
  42. 2026-05-28 13:44 UTCEPSS rescore
  43. 2026-05-27 13:40 UTCEPSS rescore
  44. 2026-05-27 13:40 UTCEPSS rescore
  45. 2026-05-27 13:40 UTCEPSS rescore
  46. 2026-05-26 13:44 UTCEPSS rescore
  47. 2026-05-26 07:18 UTCEPSS rescore
  48. 2026-05-26 07:18 UTCEPSS rescore
  49. 2026-05-23 00:08 UTCEG score recompute
  50. 2026-05-20 22:38 UTCEPSS rescore
  51. 2026-05-20 22:38 UTCEPSS rescore
  52. 2026-05-20 17:51 UTCEG score recompute
  53. 2026-05-20 11:22 UTCEPSS rescore
  54. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-40097?
CVE-2026-40097 is a low vulnerability published on April 10, 2026. Step CA is an online certificate authority for secure, automated certificate management for DevOps. From 0.24.0 to before 0.30.0-rc3, an attacker can trigger an index out-of-bounds panic in Step CA by sending a crafted attestation key (AK) certificate with an empty Extended Key Usage (EKU)…
When was CVE-2026-40097 disclosed?
CVE-2026-40097 was first published in the National Vulnerability Database on April 10, 2026, with the most recent update on April 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40097 actively exploited?
CVE-2026-40097 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 7.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40097?
CVE-2026-40097 has a CVSS v3 base score of 3.7 (NVD).
How do I remediate CVE-2026-40097?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40097, 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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