NULL pointer dereference in GnuTLS
Priority LOW 33CWE-476Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Will not fix Red Hat: no fix planned
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-476.
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.
Why it matters now
EPSS 0.01908 79th percentileScored 2026-11-07
Fix Will not fix Red Hat: no fix planned
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | GnuTLS | Fixed in gnutls v3.7.3 | — | No fix listed | CNA |
- GnuTLS Vendor— Affected Fixed in gnutls v3.7.3 Fixed in — No fix listed CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:* | before 3.7.3 | Vulnerable | GNU |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:a:netapp:solidfire_\&_hci_management_node:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:a:netapp:hci_bootstrap_os:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:hci_compute_node:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
- cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:* Versions before 3.7.3 Vulnerable ·GNU
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
- cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:a:netapp:solidfire_\&_hci_management_node:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:a:netapp:hci_bootstrap_os:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:hci_compute_node:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Will not fix |
Not affected: 1 product
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-4209
- 2026-10-03 Alias added: GHSA-xj78-h3gx-cm6v
References
Sources
- CVE-2021-4209 · CVE Program
- CVE-2021-4209 · NVD
- FIRST EPSS
- GHSA-xj78-h3gx-cm6v · GitHub Advisory Database · CC BY 4.0
- CVE-2021-4209 · Red Hat security data · CC BY 4.0
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