Is CVE-2025-53521 in the CISA KEV catalog?

Yes. CVE-2025-53521 is on the CISA Known Exploited Vulnerabilities list, added 2026-03-27.

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

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

What is the EPSS score for CVE-2025-53521?

CVE-2025-53521 has an EPSS score of 2.25% (81th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2025-53521

CRITICALCISA KEVEPSS 81th pctl

9.8

CVSS v3

NVD

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.

CWE-121

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

2.25%probability of exploitation in 30 days

81stpercentile

Elevated risk: more likely to be exploited than 81% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Remediation due: 2026-03-30

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-31.