CVE-2021-43392
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedSTMicroelectronics STSAFE-J 1.1.4, J-SAFE3 1.2.5, and J-SIGN sometimes allow attackers to obtain information on cryptographic secrets. This is associated with the ECDSA signature algorithm on the Java Card J-SAFE3 and STSAFE-J platforms exposing a 3.0.4 Java Card API. It is exploitable for STSAFE-J in closed configuration and J-SIGN (when signature verification is activated) but not for J-SAFE3 EPASS BAC and EAC products. It might also impact other products based on the J-SAFE-3 Java Card platform.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThe vulnerability allows attackers to obtain information on cryptographic secrets via the ECDSA signature algorithm on STMicroelectronics Java Card platforms (STSAFE-J and J-SIGN). This side-channel or timing-based information disclosure is exploitable when signature verification is activated on affected platforms, potentially leaking key material used in ECDSA operations.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.2.5= 1.1.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the installed STMicroelectronics Java Card firmware versionQuery the Java Card device or consult its firmware manifest to retrieve the current firmware version. This is typically accessible via device management interfaces or smart card communication tools.Affected if The firmware version matches exactly 1.2.5 for St J Safe3 or 1.1.4 for St Stsafe J
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Determine if the platform is St J Safe3 or St Stsafe JIdentify the specific product model by checking the device identification or product documentation for the Java Card platform in use.Affected if The product is St J Safe3 with firmware 1.2.5 OR St Stsafe J with firmware 1.1.4
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Check whether ECDSA signature verification is enabledInspect the platform configuration, security policy settings, or applet configuration to determine if ECDSA signature verification operations are activated or permitted.Affected if ECDSA signature verification is enabled or can be invoked on the affected firmware versions
The environment is affected if it uses St J Safe3 firmware 1.2.5 or St Stsafe J firmware 1.1.4 AND has ECDSA signature verification functionality enabled.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataContact STMicroelectronics for firmware updates that implement constant-time cryptographic operations and side-channel countermeasures for ECDSA on affected Java Card platforms.
- Consultation4.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,920.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-43392 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-43392 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data