CVE-2021-43393

Integrity bypass via improper ECDSA verification

Published Mar 4, 2022 · Updated Aug 4, 2024

Improper ECDSA verification in STSAFE-J 1.1.4, J-SAFE3 1.2.5, and J-SIGN allows local users to subvert signature checks. The ECDSA implementation exposed through the Java Card 3.0.4 API mishandles signature verification, but the failing input condition is undisclosed. Exploitation requires STSAFE-J 1.1.4 in closed configuration or J-SIGN with signature verification enabled; J-SAFE3 EPASS BAC and EAC products are not affected.

CVSS severity6.2
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper ECDSA verification in STSAFE-J 1.1.4, J-SAFE3 1.2.5, and J-SIGN allows local users to subvert signature checks. The ECDSA implementation exposed through the Java Card 3.0.4 API mishandles signature verification, but the failing input condition is undisclosed. Exploitation requires STSAFE-J 1.1.4 in closed configuration or J-SIGN with signature verification enabled; J-SAFE3 EPASS BAC and EAC products are not affected.

The record

CVE
CVE-2021-43393
Published
Mar 4, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-347, CAPEC-475, T1553
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

1.9NIST NVDAV:L/AC:M/Au:N/C:N/I:P/A:N
6.2NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
CAPEC-475Signature Spoofing by Improper Validation
T1553Subvert Trust Controls

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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