What’s Vulnerable › Vulnerabilities

CVE-2021-23008

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-05-10 · updated 2026-06-17
• Weakness: CWE-287

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.

Affected products

• F5 BIG-IP APM: from 11.5.2 before 11.6.5; from 12.1.0 before 12.1.5; from 13.1.0 before 13.1.3; from 14.1.0 before 14.1.3; from 15.0.0 before 15.1.2; from 16.0.0 before 16.0.1 — fixed in 11.6.5, 12.1.5, 13.1.3, 14.1.3, 15.1.2, 16.0.1

How to fix

Upgrade to a fixed version: F5 BIG-IP APM 11.6.5, 12.1.5, 13.1.3, 14.1.3. Check the vendor advisory for mitigations.

References

• https://support.f5.com/csp/article/K51213246
• https://support.f5.com/csp/article/K51213246

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