CVE-2021-28484: Fedoraproject Fedora

High severity, CVSS 7.5. EPSS: 1.5% chance of exploitation in the next 30 days.

An issue was discovered in the /api/connector endpoint handler in Yubico yubihsm-connector before 3.0.1 (in YubiHSM SDK before 2021.04). The handler did not validate the length of the request, which can lead to a state where yubihsm-connector becomes stuck in a loop waiting for the YubiHSM to send it data, preventing any further operations until the yubihsm-connector is restarted. An attacker can send 0, 1, or 2 bytes to trigger this.

Affected products

• Fedoraproject Fedora: version 34 only
• Yubico Yubihsm Connector: before 3.0.1 (fixed in 3.0.1)

Published 2021-04-14. Last modified 2026-06-17.