Daily Intel Brief

Daily Intel Brief — 2026-04-24

Arc Security Research ·

CVE-2025-53521 – F5 BIG-IP DoS (Actively Exploited)

WhatA CVSS 7.5 DoS vulnerability in F5 BIG-IP that is being actively exploited when an APM Access Policy is configured on a virtual server.

Source[Greenbone March 2026 Threat Report](www.greenbone.net)

Applies toOrganizations using F5 BIG-IP with APM policies

Why it mattersCISA confirms active exploitation – patch or mitigate immediately to avoid service disruption.

CVE-2026-23813 – Critical (CVSS 9.8) Unpatched

WhatA critical remote code execution vulnerability (CVSS 9.8) reported in March 2026; details sparse but score indicates pre-auth, no user interaction required.

SourceSame Greenbone report [Link](secinfo.greenbone.net)

Applies toGeneral – check for affected products

Why it mattersScore 9.8 means broad impact likely; identify and patch as soon as PoC emerges.

Bypassing Windows Administrator Protection via UI Abuse

WhatResearch describes how an attacker with limited user access can abuse UI automation to bypass Windows Administrator Protection (formerly LUA).

Source[Project Zero Feed via Feeder](feeder.co)

Applies toWindows systems with Admin Protection enabled

Why it mattersLow-privilege to admin escalation technique – review UAC/Admin Protection configurations.

CISA KEV – VMware ESXi Information Disclosure

WhatCISA added a VMware ESXi, Workstation, and Fusion info disclosure vulnerability to its Known Exploited Vulnerabilities catalog.

Source[The Cyber Express – CISA KEV Update](thecyberexpress.com)

Applies toVMware hypervisor users

Why it mattersActive exploitation means attackers are using this to leak sensitive data from virtualized environments.

CISA KEV – 5 New Flaws Including Apple Multiple

WhatCISA added five actively exploited vulnerabilities, including multiple Apple platform flaws.

Source[Reddit /r/TechNadu](www.reddit.com)

Applies toApple devices (iOS/macOS) and other appliances in catalog

Why it mattersApple enterprise devices are prime targets; ensure MDM enforces latest patches.

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