9.8 Critical Exploited

CVE-2025-53521 F5 BIG-IP Unspecified Vulnerability

Active exploitation observed

· CISA KEV catalogue

Required action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Ransomware campaigns Not observed so far

Description

When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE). Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products and versions

Product	Affected versions	Fixed in
BIG-IP 17.5	17.5.0 → < 17.5.1.3	17.5.1.3
BIG-IP 17.1	17.1.0 → < 17.1.3	17.1.3
BIG-IP 16.1	16.1.0 → < 16.1.6.1	16.1.6.1
BIG-IP 15.1	15.1.0 → < 15.1.10.8	15.1.10.8

References

my.f5.com my.f5.com

Timeline

Published October 15, 2025
Added to the KEV catalogue March 27, 2026
Last modified March 31, 2026

The 259 CVEs of BIG-IP →

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