CVE-2025-53521

9.8 CRITICAL CISA KEV - Actively Exploited

Published: October 15, 2025 Modified: April 02, 2026

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

CVSS v3.x Details

0.0 Low Medium High Critical 10.0

Vector String

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

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory

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

Source: f5sirt@f5.com

Vendor Advisory

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53521

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

US Government Resource

2 reference(s) from NVD

Quick Stats

CVSS v3 Score

9.8 / 10.0

EPSS (Exploit Probability)

41.4%

97th percentile

Exploitation Status

Actively Exploited

Remediation due: 2026-03-30

Weaknesses (CWE)

CWE-121

Affected Vendors

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