Secuno
ENNL
Book demo

CVE-2025-53521

F5 BIG-IP Stack-Based Buffer Overflow

9.8 CRITICALActively exploited (CISA KEV)EPSS 2.30%
  1. Published15 Oct 2025
  2. Added to CISA KEV27 Mar 2026
  3. Remediation due30 Mar 2026
Actively exploited (CISA KEV)

F5 BIG-IP APM contains a stack-based buffer overflow vulnerability that could allow a threat actor to achieve remote code execution.

Added to KEV: 27 Mar 2026Federal remediation due: 30 Mar 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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

F5 Big-ip Access Policy Manager≥ 15.1.0 < 15.1.10.8 · ≥ 16.1.0 < 16.1.6.1 · ≥ 17.1.0 < 17.1.3 · ≥ 17.5.0 < 17.5.1.3

Remediation

Fixed in
F5 Big-ip Access Policy Manager≥ 15.1.10.8

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-10910910.0
A vulnerability was detected in Wavlink WL-WN530BE1-A 251117. This vulnerability…
CVE-2026-854578.1
IBM Planning Analytics 2.0, and 2.1 could allow a remote authenticated attacker to…
CVE-2026-962668.2
IBM Power Systems Firmware FW1060.00 through FW1060.81 is affected by a vulnerability…
CVE-2026-962648.2
IBM Power Systems Firmware FW1060.00 through FW1060.81 is affected by a vulnerability…
CVE-2026-962638.2
IBM Power Systems Firmware FW1120.00 through FW1120.01, FW1110.00 through FW1110.31,…
CVE-2026-962628.2
IBM Power Systems Firmware FW1060.00 through FW1060.81 is affected by a vulnerability…

Frequently asked

Is CVE-2025-53521 being actively exploited?

Yes. CVE-2025-53521 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 27 Mar 2026.

How severe is CVE-2025-53521?

CVE-2025-53521 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 2.30% probability of exploitation.

Which products are affected by CVE-2025-53521?

Affected products include F5 Big-ip Access Policy Manager.

How do I fix CVE-2025-53521?

Upgrade affected software to a fixed version, for example F5 Big-ip Access Policy Manager 15.1.10.8 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-53521 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.