CVE-2021-4209

MediumCVSS 6.5/10Last modified Oct 14, 2026

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.

Metrics

CVSS 3.1 6.5/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

CWE-476

Affected software

Vendor	Product	Versions
n/a	GnuTLS	Fixed in gnutls v3.7.3
Siemens	SIMATIC S7-1500 CPU 1518-4 PN/DP MFP	>= V3.1.0, < V3.1.5
Siemens	SIMATIC S7-1500 CPU 1518-4 PN/DP MFP	>= V3.1.0, < V3.1.5
Siemens	SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP	>= V3.1.0, < V3.1.5
Siemens	SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP	>= V3.1.0, < V3.1.5
Siemens	SIPLUS S7-1500 CPU 1518-4 PN/DP MFP	>= V3.1.0, < V3.1.5

References

https://access.redhat.com/security/cve/CVE-2021-4209Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2044156Issue Tracking, Third Party Advisory
https://gitlab.com/gnutls/gnutls/-/commit/3db352734472d851318944db13be73da61300568Patch, Third Party Advisory
https://gitlab.com/gnutls/gnutls/-/issues/1306Third Party Advisory
https://gitlab.com/gnutls/gnutls/-/merge_requests/1503Third Party Advisory
https://security.netapp.com/advisory/ntap-20220915-0005/Third Party Advisory
https://access.redhat.com/security/cve/CVE-2021-4209Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2044156Issue Tracking, Third Party Advisory
https://gitlab.com/gnutls/gnutls/-/commit/3db352734472d851318944db13be73da61300568Patch, Third Party Advisory
https://gitlab.com/gnutls/gnutls/-/issues/1306Third Party Advisory
https://gitlab.com/gnutls/gnutls/-/merge_requests/1503Third Party Advisory
https://security.netapp.com/advisory/ntap-20220915-0005/Third Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-398330.html

Timeline

Published: Aug 24, 2022
Last modified: Oct 14, 2026
NVD status: Modified

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