What’s Vulnerable › Vulnerabilities

CVE-2021-4209

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-08-24 · updated 2026-10-14
• Weakness: CWE-476

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.

Affected products

• [UNKNOWN] gnutls: before 3.7.3 — fixed in 3.7.3
• Active IQ Unified Manager for VMware vSphere, Linux, and Microsoft Windows: all versions
• NetApp Hci Bootstrap Os: all versions
• NetApp Solidfire & Hci Management Node: all versions
• Red Hat Enterprise Linux: 8.0

How to fix

Upgrade to a fixed version: [UNKNOWN] gnutls 3.7.3. Check the vendor advisory for mitigations.

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
• https://security.netapp.com/advisory/ntap-20220915-0005/
• 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
• https://security.netapp.com/advisory/ntap-20220915-0005/

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