CVE-2025-53521

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.

CVSS v3.1 Score

9.8

CRITICAL

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

CISA Known Exploited Vulnerability

This vulnerability is actively exploited in the wild.

Added: Mar 27, 2026 Remediation due: Mar 30, 2026

Weakness Type (CWE)

CWE-121 CWE-121

Affected Products

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

Advisories & Patches

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

Other References

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

Frequently Asked Questions

What is CVE-2025-53521? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2025-53521? +

CVE-2025-53521 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2025-53521? +

CVE-2025-53521 affects products from f5, specifically: big-ip_access_policy_manager. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-53521? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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