Improper Validation of Array Index Affecting github.com/smallstep/certificates/acme package, versions >=0.24.0 <0.30.0-rc3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMSMALLSTEPCERTIFICATESACME-15969262
- published10 Apr 2026
- disclosed10 Apr 2026
- creditOleh Konko
Introduced: 10 Apr 2026
CVE-2026-40097 Â (opens in a new tab)How to fix?
Upgrade github.com/smallstep/certificates/acme to version 0.30.0-rc3 or higher.
Overview
Affected versions of this package are vulnerable to Improper Validation of Array Index of tcg-kp-AIKCertificate Extended Key Usage OID during TPM device attestation. An attacker can cause a panic and disrupt service availability by submitting a crafted attestation key certificate with an empty EKU extension. This is only exploitable if a device-attest-01 ACME challenge with TPM attestation is configured.