CVE-2021-42023

Name: CVE-2021-42023
Creator: NVD / NIST
Published: 2021-12-14T12:15:09.917+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.56%

Last modified Jun 17, 2026

CVE-2021-42023 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. A vulnerability has been identified in ModelSim Simulation (All versions), Questa Simulation (All versions). The RSA white-box implementation in affected applications insufficiently protects the built-in private keys that are required to decrypt electronic intellectual property (IP) data in accordance with the IEEE 1735 recommended practice. EPSS estimates a 0.56% chance of exploitation in the next 30 days.

Description

A vulnerability has been identified in ModelSim Simulation (All versions), Questa Simulation (All versions). The RSA white-box implementation in affected applications insufficiently protects the built-in private keys that are required to decrypt electronic intellectual property (IP) data in accordance with the IEEE 1735 recommended practice. This could allow a sophisticated attacker to discover the keys, bypassing the protection intended by the IEEE 1735 recommended practice.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.56%

42.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-522

Affected Software

Vendor	Product	Versions
Siemens	Modelsim	All versions
Siemens	Questa	All versions

References

https://cert-portal.siemens.com/productcert/pdf/ssa-400332.pdfPatch, Vendor Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-400332.pdfPatch, Vendor Advisory

Timeline

Published: Dec 14, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42023?

How severe is CVE-2021-42023?

CVE-2021-42023 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42023?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-42023?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST