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CVE-2025-53521 is a critical vulnerability in F5 BIG-IP Access Policy Manager (APM). When an APM access policy is configured on a virtual server, specific malicious traffic sent to the affected service can trigger remote code execution in the data-plane processing path, including the apmd process. The issue was initially disclosed as a denial-of-service condition but was later reclassified in March 2026 after F5 determined that the same flaw could be exploited for unauthenticated remote code execution. Affected supported versions include BIG-IP APM 15.1.0 through 15.1.10, 16.1.0 through 16.1.6, 17.1.0 through 17.1.2, and 17.5.0 through 17.5.1. Appliance mode systems are also affected. Publicly available material does not provide sufficient technical detail to confidently identify the precise root cause or map the issue to a specific CWE.
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No public exploit code observed for this vulnerability.
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
175 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An F5 BIG-IP APM vulnerability referenced as an example of active exploitation against internet-facing edge appliances.
An F5 BIG-IP APM vulnerability referenced as part of the broader pattern of edge appliance exploitation, with explicit mention of active exploitation and KEV inclusion.
A critical remote code execution vulnerability in F5 BIG-IP APM that can be triggered by specially crafted malicious traffic when an access policy is enabled on a virtual server.
A critical vulnerability in F5 BIG-IP Access Policy Manager (APM) that was initially classified as a denial-of-service issue but later understood to enable remote code execution, creating significant risk of full appliance compromise and internal network intrusion.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.