{"id":"EUVD-2026-21506","revision":"520ceb36b2164959b09c3a5e705ce465","records":[{"revision":"520ceb36b2164959b09c3a5e705ce465","observedAt":"2026-11-01T06:15:12.2+00:00","statement":{"source":"euvd","id":"EUVD-2026-21506","aliases":["CVE-2026-40097","GHSA-9qq8-cgcv-qmc9"],"title":"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) …","description":"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.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","score":3.7,"severity":null}],"references":["https://github.com/smallstep/certificates/security/advisories/GHSA-9qq8-cgcv-qmc9","https://github.com/smallstep/certificates/pull/2569","https://github.com/smallstep/certificates/commit/ffd31ac0a87e03b0224cb8363094bfe602242888","https://github.com/smallstep/certificates/releases/tag/v0.30.0"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-21506","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Apr 10, 2026, 4:34:53 PM","dateUpdated":"Apr 10, 2026, 6:30:15 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-21506","identifiers":["EUVD-2026-21506","CVE-2026-40097","GHSA-9qq8-cgcv-qmc9"]},"retained":false,"historicalAffected":[]}],"coverage":[]}