{"cve":"CVE-2021-4209","nvd":{"published":"2022-08-24T16:15:09.927","modified":"2026-10-14T11:16:55.207","status":"Modified","description":"A NULL pointer dereference flaw was found in GnuTLS. As Nettle's hash update functions internally call memcpy, providing zero-length input may cause undefined behavior. This flaw leads to a denial of service after authentication in rare circumstances.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-476"],"references":["https://access.redhat.com/security/cve/CVE-2021-4209","https://bugzilla.redhat.com/show_bug.cgi?id=2044156","https://gitlab.com/gnutls/gnutls/-/commit/3db352734472d851318944db13be73da61300568","https://gitlab.com/gnutls/gnutls/-/issues/1306","https://gitlab.com/gnutls/gnutls/-/merge_requests/1503"],"products":["gnu:gnutls","netapp:active_iq_unified_manager","netapp:hci_bootstrap_os","netapp:solidfire_\\&_hci_management_node","redhat:enterprise_linux"],"source":"nvd","synced_at":"2026-10-19T21:34:18.502168378+00:00"},"epss":{"cve":"CVE-2021-4209","score":0.01908,"percentile":0.7962,"date":"2026-10-25"},"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."]}