How severe is CVE-2021-23032?

CVE-2021-23032 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-23032 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-23032?

CVE-2021-23032 affects F5 Big-ip Domain Name System. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-23032?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-23032 published?

CVE-2021-23032 was published on 2021-09-14 and last updated on 2026-06-17.

CVE-2021-23032

CVE-2021-23032 is a high-severity vulnerability in F5 Big-ip Domain Name System with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: F5 Big-ip Domain Name System
Published: 2021-09-14
Last modified: 2026-06-17

Description

On version 16.x before 16.1.0, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.4, and all versions of 13.1.x and 12.1.x, when a BIG-IP DNS system is configured with non-default Wide IP and pool settings, undisclosed DNS responses can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Frequently asked questions

What is CVE-2021-23032?: On version 16.x before 16.1.0, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.4, and all versions of 13.1.x and 12.1.x, when a BIG-IP DNS system is configured with non-default Wide IP and pool settings, undisclosed DNS responses can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
How severe is CVE-2021-23032?: CVE-2021-23032 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-23032 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-23032?: CVE-2021-23032 affects F5 Big-ip Domain Name System. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-23032?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-23032 published?: CVE-2021-23032 was published on 2021-09-14 and last updated on 2026-06-17.

References

https://support.f5.com/csp/article/K45407662

Affected products (1)

cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*

More vulnerabilities in F5 Big-ip Domain Name System

CVE-2023-41373 — Critical (CVSS 9.9): A directory traversal vulnerability exists in the BIG-IP Configuration Utility that may allow an authenticated attacker…
CVE-2021-22987 — Critical (CVSS 9.9): On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x…
CVE-2023-46747 — Critical (CVSS 9.8): Undisclosed requests may bypass configuration utility authentication, allowing an attacker with network access to the…
CVE-2022-1388 — Critical (CVSS 9.8): On F5 BIG-IP 16.1.x versions prior to 16.1.2.2, 15.1.x versions prior to 15.1.5.1, 14.1.x versions prior to 14.1.4.6,…
CVE-2021-22991 — Critical (CVSS 9.8): On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and…
CVE-2021-22992 — Critical (CVSS 9.8): On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x…

All CVEs affecting F5 Big-ip Domain Name System →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →