{"cve":"CVE-2021-43399","nvd":{"published":"2021-12-08T19:15:10.020","modified":"2026-06-17T04:10:55.120","status":"Modified","description":"The Yubico YubiHSM YubiHSM2 library 2021.08, included in the yubihsm-shell project, does not properly validate the length of some operations including SSH signing requests, and some data operations received from a YubiHSM 2 device.","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-787"],"references":["https://blog.inhq.net/posts/yubico-yubihsm-shell-vuln3/","https://www.yubico.com/support/security-advisories/ysa-2021-04/","https://blog.inhq.net/posts/yubico-yubihsm-shell-vuln3/","https://www.yubico.com/support/security-advisories/ysa-2021-04/"],"products":["yubico:yubihsm_2_software_development_kit"],"source":"nvd","synced_at":"2026-10-19T21:25:41.256909649+00:00"},"epss":{"cve":"CVE-2021-43399","score":0.01413,"percentile":0.72721,"date":"2026-11-01"},"kev":null,"osv":[],"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."]}