CVE-2021-42023: Siemens Modelsim

Medium severity, CVSS 6.5. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• Siemens Modelsim: any version
• Siemens Questa: any version

Published 2021-12-14. Last modified 2026-06-17.