Two unpatched Windows Defender zero-days have been actively exploited since April 16th, and both of them work on fully patched Windows 10, Windows 11, and Server 2019 and later, including machines that installed this month’s Patch Tuesday updates. One of them makes Defender write the attacker’s payload into System32 by itself, then stands back and lets Windows run it as SYSTEM. The other blocks Defender from receiving any new virus definitions and lies to the EDR management console about it, showing green checkmarks on machines that are already fully compromised. 😏

iTerm2, the terminal emulator that ends up on almost every Mac developer’s machine, is vulnerable to a remote code execution attack that occurs when attacker-controlled text is displayed in the terminal, most commonly through reading a file with cat, less, or head. CVE-2026-41253, disclosed on April 17, covers every stable release up through version 3.6.9, which is still the current build on the downloads page because the fix that landed in source on March 31 has not yet shipped in a new release. Researchers at Calif Global turned a plain file-display operation into a full shell as the logged-in user by abusing a legitimate SSH integration feature that iTerm2 trusts by default, without a single click, a single download, or a single signature for any security tool to catch. 😏

Microsoft 365 mailbox rules are being weaponized as a core technique behind $2.77 billion in annual Business Email Compromise losses, and attackers are creating hidden rules that survive password resets, MFA enrollment, and session invalidation. A new Proofpoint report reveals that 10% of all compromised Microsoft 365 accounts get malicious inbox rules installed within seconds of the initial breach, targeting 400+ million users worldwide by abusing built-in email functionality no security tool will ever flag as suspicious. 😏

A critical vulnerability in nginx-ui has been actively exploited since March 2026, and it gives any attacker on the network full control over the nginx server behind it without a single credential. CVE-2026-33032 scores 9.8 on the CVSS scale, sits inside an AI integration that was added to the tool in late 2025, and the entire root cause turned out to be 27 characters of missing code. Recorded Future assigned it a risk score of 94 out of 100. The researchers who found it named it MCPwn. 😏

PHP Composer Has Two Flaws That Run Arbitrary Commands on Developer Machines PHP Composer, the package manager that almost every PHP developer uses to build websites and applications, has two serious vulnerabilities that allow an attacker to run arbitrary commands on any machine running a vulnerable version. Neither one requires Perforce to be installed, configured, or even known about. Patches came out on April 14, 2026, and many environments will still be running vulnerable versions. 😏

MSBuild.exe is a LOLBin, a legitimate Windows tool being abused to run malware on fully patched machines without dropping a single file on disk, and Windows Defender does not raise an alert because MSBuild.exe carries Microsoft’s own digital signature and many security tools treat it as trusted by default. There is no patch coming because nothing here is broken. MSBuild.exe is doing exactly what Microsoft designed it to do. 😏

MSBuild.exe, the Microsoft Build Engine, has been part of the .NET Framework and Visual Studio for years. Software developers use it to compile and build applications from XML-based project files. Because Microsoft built it and signed it, Windows trusts it completely. AppLocker trusts it. Windows Defender Application Control trusts it. Most endpoint security solutions wave it through without a second look, because as far as they are concerned, it is a legitimate Microsoft tool doing its job.

Docker’s Security Layer Has Been Broken Since 2016, And The Fix Doesn’t Finish the Job. One padded HTTP request. That is all it takes to silently disable every authorization plugin in Docker, open a direct path to the host filesystem, and walk out with AWS credentials, SSH keys, and Kubernetes cluster access. The authorization logs show nothing unusual. 😏

When a request hits the Docker API, an authorization plugin steps in before anything else happens. That plugin checks exactly what is being requested before the Docker daemon gets to act on it, and enterprises run tools like Open Policy Agent, Prisma Cloud, or Casbin for this job, configured with rules about what containers are and are not allowed to do.

A Remote Access Trojan called DesckVB has been actively hitting systems throughout 2026, running almost entirely inside memory with barely anything written to disk, hiding its final payload inside a process it names Microsoft.exe, and attempting to switch off the camera LED before streaming video back to the attacker. A cracked version of the builder is already circulating freely, meaning attackers with minimal skills can deploy this today without writing a single line of code. Forensics teams sweep these machines afterward and find very little. The system looks completely clean. 😏

Windows Defender, the built-in antivirus running on every Windows machine, has a zero-day exploit with full source code sitting on GitHub. No patch, no CVE, and confirmed working on fully updated Windows 10 and 11. A researcher who says Microsoft went back on their word just handed every attacker paying attention a privilege escalation that takes any low-privileged account straight to NT AUTHORITY\SYSTEM. On Windows Server the result is different but still serious: a standard user ends up with elevated administrator access. 😏

Fiber optic cables running through your walls can be turned into hidden microphones that record every word spoken in the room. This is not a theory anymore. Researchers from Hong Kong Polytechnic University published a fully working attack at the NDSS Symposium in February 2026, and the results are going to change the way a lot of people think about what is running through their walls. 😏

I refused to get fiber optic internet installed at my house. Call it a security instinct. Everyone around me thought I was being paranoid. Turns out that feeling was right.