CVE-2025-53521

CriticalActively exploited (CISA KEV)

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.

SeverityCritical

CVSS9.8

Exploit probability—

Product

F5 BIG-IP

PublishedOct 15, 2025

First seenOct 15, 2025

Added to KEVMar 27, 2026

Weakness typeCWE-121CWE-121

How to fix

CISA 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.

CISA due date: Mar 30, 2026

Update

f5 big-ip_access_policy_manager15.1.10.8, 16.1.6.1, 17.1.3, 17.5.1.3 or later

Vendor advisories

my.f5.com/manage/s/article/K000156741

Affected products

Product	Affected versions	Fixed in
f5 big-ip_access_policy_manager	15.1.0 ≤ v < 15.1.10.8, 16.1.0 ≤ v < 16.1.6.1, 17.1.0 ≤ v < 17.1.3, 17.5.0 ≤ v < 17.5.1.3	15.1.10.8, 16.1.6.1, 17.1.3, 17.5.1.3

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