CVE-2025-53521

Name: CVE-2025-53521
Creator: NVD / NIST
Published: 2025-10-15T14:15:48.377+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.3/10Actively ExploitedEPSS 2.25%

Last modified Jun 17, 2026

CVE-2025-53521 is a critical-severity vulnerability rated 9.3/10 on the CVSS scale. 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.. CISA has confirmed active exploitation in the wild. EPSS estimates a 2.25% chance of exploitation in the next 30 days.

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.

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

CVSS 4.0

9.3/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

2.25%

80.6th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Mar 30, 2026.

Weakness Enumeration

CWE-121

Affected Software

Vendor	Product	Versions
F5	Big-Ip Access Policy Manager	>= 15.1.0, < 15.1.10.8
F5	Big-Ip Access Policy Manager	>= 16.1.0, < 16.1.6.1
F5	Big-Ip Access Policy Manager	>= 17.1.0, < 17.1.3
F5	Big-Ip Access Policy Manager	>= 17.5.0, < 17.5.1.3

References

https://my.f5.com/manage/s/article/K000156741Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53521US Government Resource

Timeline

Published: Oct 15, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-53521?

How severe is CVE-2025-53521?

CVE-2025-53521 has a CVSS score of 9.3/10 (CRITICAL severity). The EPSS model estimates a 2.25% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2025-53521?

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-2025-53521?

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

Scan your code now

Source: NVD / NIST