HOMEVULNERABILITIESCVE-2021-43393
MEDIUM

CVE-2021-43393

CWE-347Published: March 4, 2022· Updated: Jun 17, 2026

6.2
CVSS v3.1

Official Description

STMicroelectronics STSAFE-J 1.1.4, J-SAFE3 1.2.5, and J-SIGN sometimes allow attackers to abuse signature verification. 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.

NVD Source

Technical Analysis

CVE-2021-43393 requires local access, meaning attackers must already have a foothold on the target system.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in full integrity compromise (data manipulation), with a CVSS base score of 6.2.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected Vendors & Products

st4 product(s)
stsafe-j firmwarestsafe-jj-safe3 firmwarej-safe3
Source: NVD CPE · 4 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://community.st.com/s/toparticles
ADVISORYhttps://www.cert.ssi.gouv.fr/avis/CERTFR-2022-AVI-169/
ADVISORYhttps://community.st.com/s/toparticles
ADVISORYhttps://www.cert.ssi.gouv.fr/avis/CERTFR-2022-AVI-169/

All References (4)

→
https://community.st.com/s/toparticlesVendor Advisory
→
https://www.cert.ssi.gouv.fr/avis/CERTFR-2022-AVI-169/Third Party Advisory
→
https://community.st.com/s/toparticlesVendor Advisory
→
https://www.cert.ssi.gouv.fr/avis/CERTFR-2022-AVI-169/Third Party Advisory

Quick Facts

CVE IDCVE-2021-43393
CVSS Score6.2 / 10
SeverityMEDIUM
WeaknessCWE-347
CISA KEVNo
Affected1 vendor(s)
PublishedMar 4, 2022

Related CVEs (CWE-347)

CVE-2024-32962
10.0
CVE-2026-56451
10.0
CVE-2026-48558
KEV10.0
CVE-2026-44748
9.9
CVE-2023-23928
9.8
CVE-2022-25898
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-43393 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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