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.
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/