{"cve":"CVE-2021-28484","nvd":{"published":"2021-04-14T18:15:14.440","modified":"2026-06-17T03:46:26.923","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-835"],"references":["https://github.com/Yubico/yubihsm-connector/releases","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B7Q2KGXSPQEEONAWMFZRVH2TXWX3QPCQ/","https://www.yubico.com/support/security-advisories/ysa-2021-02/","https://github.com/Yubico/yubihsm-connector/releases","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B7Q2KGXSPQEEONAWMFZRVH2TXWX3QPCQ/"],"products":["fedoraproject:fedora","yubico:yubihsm_connector"],"source":"nvd","synced_at":"2026-10-19T21:17:01.373894544+00:00"},"epss":{"cve":"CVE-2021-28484","score":0.01521,"percentile":0.74603,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-8m9g-647g-5pxw","url":"https://osv.dev/vulnerability/GHSA-8m9g-647g-5pxw","summary":"Infinite loop in Yubico yubihsm-connector","modified":"2023-11-08T04:05:30.407376Z","packages":[{"ecosystem":"Go","name":"github.com/Yubico/yubihsm-connector","purl":"pkg:golang/github.com/Yubico/yubihsm-connector","ranges":["<3.0.1"],"fixed":["3.0.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}