Microsoft Office Zero-Day Exploited Days After Emergency Patch, Update ASAP

A hole in Microsoft Office is being exploited by bad actors, including Russian hackers targeting Ukraine's government.

Russian hackers exploit recently patched Microsoft Office bug in attacks

Ukraine's Computer Emergency Response Team (CERT) says that Russian hackers are exploiting CVE-2026-21509, a recently patched vulnerability in multiple versions of Microsoft Office.
Dark Reading

Russian Hackers Weaponize Microsoft Office Bug in Just 3 Days

APT28's attacks use specially crafted Microsoft Rich Text Format (RTF) documents to kick off a multistage infection chain to deliver malicious payloads.
The Hacker News

APT28 Uses Microsoft Office CVE-2026-21509 in Espionage-Focused Malware Attacks

APT28 exploited a Microsoft Office flaw to deliver MiniDoor and Covenant Grunt malware in targeted attacks across Ukraine and Eastern Europe.

Russia-linked APT28 attackers already abusing new Microsoft Office zero-day

Ukraine’s CERT says the bug went from disclosure to active exploitation in days Russia-linked attackers are already ...
CSO Online

Notepad++ infrastructure hijacked by Chinese APT in sophisticated supply chain attack

The hosting provider's compromise allowed attackers to deliver malware through tainted software updates for six months.

The Notepad++ website was hijacked by 'malicious actors' last year and security researchers are picking through the wreckage

It's believed that, between June and November 10/December 2, 2025 (independent security experts and its hosting provider ...