CVE-2025-53521

CRITICALNVD 9.89.8—Trending — 4 sources updated this weekExploited in the wild

9.8

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: 9.8
EG Score: 9.8(high)
EPSS: 92.7%
KEV: ⚠ Exploited

Published

October 15, 2025

Last Modified

April 2, 2026

Advisory Details (2)

Auto-updated May 18, 2026

⚠️ Active exploitation confirmed. Patch available. Sources: cisa.

cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

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

generic

myF5

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

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 20× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-05 13:22 UTCEG score recompute
2026-06-05 13:22 UTCGHSA enrichment
2026-06-05 08:58 UTCEG score recompute
2026-06-05 08:57 UTCGHSA enrichment
2026-06-05 06:10 UTCepss_batch
2026-06-05 06:10 UTCepss_batch
2026-06-05 04:34 UTCEG score recompute
2026-06-05 04:34 UTCGHSA enrichment
2026-06-05 00:10 UTCEG score recompute
2026-06-05 00:10 UTCGHSA enrichment
2026-06-04 19:46 UTCEG score recompute
2026-06-04 19:46 UTCGHSA enrichment
2026-06-04 15:22 UTCEG score recompute
2026-06-04 15:22 UTCGHSA enrichment
2026-06-04 13:12 UTCepss_batch
2026-06-04 13:12 UTCepss_batch
2026-06-04 10:58 UTCEG score recompute
2026-06-04 10:58 UTCGHSA enrichment
2026-06-04 06:34 UTCEG score recompute
2026-06-04 06:34 UTCGHSA enrichment

Frequently asked(6)

What is CVE-2025-53521?

CVE-2025-53521 is a critical vulnerability published on October 15, 2025. 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.

When was CVE-2025-53521 disclosed?

CVE-2025-53521 was first published in the National Vulnerability Database on October 15, 2025, with the most recent update on April 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2025-53521 actively exploited?

Yes. CISA added CVE-2025-53521 to the Known Exploited Vulnerabilities catalog on March 27, 2026, affecting F5 BIG-IP. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.

What is the CVSS score of CVE-2025-53521?

CVE-2025-53521 has a CVSS v3 base score of 9.8 (NVD).

Which products are affected by CVE-2025-53521?

CVE-2025-53521 affects F5 BIG-IP. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.

How do I remediate CVE-2025-53521?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-53521, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2025-53521

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Is Your Infrastructure Affected by CVE-2025-53521?

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CVE-2025-53521

📅 Published

🔄 Last Modified

📋 Advisory Details (2)