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Vulnerability details: VCID-43bp-nbru-s3f6
Vulnerability ID VCID-43bp-nbru-s3f6
Aliases CVE-2021-4209
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 5.9
Risk 3.0
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-476 NULL Pointer Dereference
System Score Found at
cvssv3 6.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-4209.json
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-4209
cvssv3.1 6.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv3.1 6.5 https://nvd.nist.gov/vuln/detail/CVE-2021-4209
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-4209.json
https://access.redhat.com/security/cve/CVE-2021-4209
https://api.first.org/data/v1/epss?cve=CVE-2021-4209
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-4209
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
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/
2044156 https://bugzilla.redhat.com/show_bug.cgi?id=2044156
cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:*
cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*
cpe:2.3:a:netapp:solidfire_\&_hci_management_node:-:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:netapp:solidfire_\&_hci_management_node:-:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
CVE-2021-4209 https://nvd.nist.gov/vuln/detail/CVE-2021-4209
USN-5550-1 https://usn.ubuntu.com/5550-1/
USN-5750-1 https://usn.ubuntu.com/5750-1/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-4209.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-4209
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.36067
EPSS Score 0.00148
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:37:37.963228+00:00 Ubuntu USN Importer Import https://usn.ubuntu.com/5750-1/ 37.0.0