Description
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.
References (3)
Core 3
Core References
Third Party Advisory x_refsource_misc
https://github.com/Yubico/yubihsm-connector/releases
Vendor Advisory x_refsource_misc
https://www.yubico.com/support/security-advisories/ysa-2021-02/
Mailing List, Third Party Advisory vendor-advisory
x_refsource_fedora
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B7Q2KGXSPQEEONAWMFZRVH2TXWX3QPCQ/
Scores
CVSS v3
7.5
EPSS
0.0056
EPSS Percentile
68.4%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Details
CWE
CWE-835
Status
published
Products (3)
fedoraproject/fedora
34
Yubico/yubihsm-connector
0 - 3.0.1Go
yubico/yubihsm_connector
< 3.0.1
Published
Apr 14, 2021
Tracked Since
Feb 18, 2026