CVE-2021-23008

Name: CVE-2021-23008
Creator: NVD / NIST
Published: 2021-05-10T14:15:07.483+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.33%

Last modified Jun 17, 2026

CVE-2021-23008 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. On version 15.1.x before 15.1.3, 14.1.x before 14.1.4, 13.1.x before 13.1.4, 12.1.x before 12.1.6, and all versions of 16.0.x and 11.6.x., BIG-IP APM AD (Active Directory) authentication can be bypassed via a spoofed AS-REP (Kerberos Authentication Service Response) response sent over a hijacked KDC (Kerberos Key Distribution Center) connection or from an AD server compromised by an attacker. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.. EPSS estimates a 1.33% chance of exploitation in the next 30 days.

Description

On version 15.1.x before 15.1.3, 14.1.x before 14.1.4, 13.1.x before 13.1.4, 12.1.x before 12.1.6, and all versions of 16.0.x and 11.6.x., BIG-IP APM AD (Active Directory) authentication can be bypassed via a spoofed AS-REP (Kerberos Authentication Service Response) response sent over a hijacked KDC (Kerberos Key Distribution Center) connection or from an AD server compromised by an attacker. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

1.33%

67.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
F5	Big-Ip Access Policy Manager	>= 11.5.2, < 11.6.5
F5	Big-Ip Access Policy Manager	>= 12.1.0, < 12.1.5
F5	Big-Ip Access Policy Manager	>= 13.1.0, < 13.1.3
F5	Big-Ip Access Policy Manager	>= 14.1.0, < 14.1.3
F5	Big-Ip Access Policy Manager	>= 15.0.0, < 15.1.2
F5	Big-Ip Access Policy Manager	>= 16.0.0, < 16.0.1

References

https://support.f5.com/csp/article/K51213246Vendor Advisory
https://support.f5.com/csp/article/K51213246Vendor Advisory

Timeline

Published: May 10, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-23008?

How severe is CVE-2021-23008?

CVE-2021-23008 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.33% probability of exploitation in the next 30 days.

How do I fix CVE-2021-23008?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-23008?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST