Index out-of-bounds panic via crafted AK certificate with empty EKU in TPM device attestation

F-SMALLSTEP-AK-EKU-001

Public snapshot: 26 Sep 2026. Status, releases and attribution belong to each source below; none is inferred from another record.

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Recorded evidence

3.7low

CVE-2026-40097CVEsmallstep/certificates

Index out-of-bounds panic via crafted AK certificate with empty EKU in TPM device attestation

Fixed in: v0.30.0

patched

details

Finding IDs: F-SMALLSTEP-AK-EKU-001
CVE: CVE-2026-40097
GHSA: GHSA-9qq8-cgcv-qmc9
Status: patched
Fixed in: v0.30.0
Recorded credit: Oleh Konko (@1seal)
Note: GHSA-9qq8-cgcv-qmc9
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CVE registry state: PUBLISHED
CVE state checked: 23 Sep 2026
Upstream title: Index out-of-bounds panic via crafted AK certificate with empty EKU in TPM device attestation
Upstream CWE: CWE-129
Upstream publication: 10 Apr 2026
Upstream updated: 10 Apr 2026
Metadata fetched: 23 Sep 2026
Upstream @1seal credit: @1seal: reporter (accepted)

F-SMALLSTEP-AK-EKU-001: Input / state handling. An empty EKU input reaches a panic, not an established authorization bypass. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-SMALLSTEP-AK-EKU-001

Security area (1seal assessment): Availability. An empty EKU input reaches a panic, not an established authorization bypass. Reviewed 24 Sep 2026.

—score not recorded

smallstep/certificatesReported fixsmallstep/certificates

Validate tcg-kp-AIKCertificate EKU

fixed publicly

details

Finding IDs: F-SMALLSTEP-AK-EKU-001
Status: fixed publicly
Reported via: security contact
Note: TPM attestation EKU panic. public fix PR #2569, first released in v0.30.0. GHSA-9qq8-cgcv-qmc9 / CVE-2026-40097 published.

F-SMALLSTEP-AK-EKU-001: Input / state handling. An empty EKU input reaches a panic, not an established authorization bypass. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-SMALLSTEP-AK-EKU-001

Security area (1seal assessment): Availability. An empty EKU input reaches a panic, not an established authorization bypass. Reviewed 24 Sep 2026.

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