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The Security Brief
How AI is changing the risk to your company's security, and what to ask your security lead. Sourced, short, and ranked by what needs action.
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Briefs
One topic each, every week, free by email. Every claim is sourced and labeled, so you can see what is proven and what is still a vendor claim. Five minutes to read.
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This week in the Security Brief
Latest issue · Oct 19, 2026
Windows, firewalls and email filters attacked before fixes arrived
Several products that companies rely on to connect staff, screen email and run their computers were attacked this week before most companies had installed the fixes. Microsoft fixed a Windows flaw that attackers were already using to slip harmful files past a built-in warning. Ivanti, which makes remote-access equipment (the device staff go through to reach the company network from home), was broken into using three flaws before fixes existed; one is still unfixed. Palo Alto Networks, one of the largest firewall makers, and Cisco, the networking company, each confirmed attacks on their equipment. And a suspected Chinese government-linked group spent weeks inside companies through BeyondTrust, software IT teams use to take over a computer remotely to fix it. Fixes are now arriving after the attacks, not before.
- CriticalMicrosoft confirms actively exploited Windows security flaw in October patches
- CriticalChinese spies exploit remote-access software used by large enterprises
- CriticalAttackers exploit Ivanti VPN flaws before patches were issued
- CriticalPalo Alto firewall flaw actively exploited; patches released
and 2 critical items, 4 important items, plus 74 more noted briefly
Read the issuePast issues
The Security Brief · 5 issues
- Read ›
Windows, firewalls and email filters attacked before fixes arrived
Several products that companies rely on to connect staff, screen email and run their computers were attacked this week before most companies had installed the fixes.
6 critical·4 importantRead › - Read ›
Attackers are exploiting remote-access flaws within days of a fix
This week, attackers exploited a SonicWall flaw three days after its fix and an Atlassian flaw about two hours after proof-of-concept code was published, while federal agencies warned of mass credential theft from remote-access devices.
4 critical·6 importantRead › - Read ›
Citrix gateway appliances actively exploited across government and finance sectors, and 9 more
Four critical vulnerabilities are being actively exploited this week across Citrix network gateways, Apple mobile and desktop devices, Microsoft SharePoint, and Fortinet email gateways, meaning companies running any of these products on older software versions may already have attackers present in their systems before patches became available.
4 critical·6 importantRead › - Read ›
Agent Data Breach | AI C2 Implant | Cloud Credentials
3 itemsRead › - Read ›
China AI Distillation | Agent Access Chains | CEO Fraud
3 itemsRead ›