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CVE-2026-21509

exploited in the wild☆ pin

CVSS

9.9

Reports

10

First seen

Jan 27, 2026

Last seen

Jul 10, 2026

Affected product

Microsoft Office 2016, 2019, 2021, 2024; Microsoft 365 Apps for Enterprise

Recent reports

June 2026 CVE Landscape: 60 High-Impact Vulnerabilities Actively Exploited

Recorded Future InsiktJul 10, 2026 Critical

Gamaredon Exploits WinRAR to Deliver GammaWorm and GammaSteel Against Ukraine

The Hacker NewsJun 2, 2026 High

Exploits and vulnerabilities in Q1 2026

Kaspersky SecurelistMay 7, 2026 Critical

Pawn Storm Campaign Deploys PRISMEX, Targets Government and Critical Infrastructure Entities

Trend Micro ResearchMar 26, 2026 Critical

Sednit reloaded: Advanced implant team returns with BeardShell and Covenant

ESET WeLiveSecurityMar 10, 2026 High

CERT-EU Cyber Brief February 2026: APT28, China espionage, AI supply-chain attacks, Qilin ransomware

CERT-EU Threat IntelMar 2, 2026 Critical

January 2026 CVE Landscape: 23 Critical Vulnerabilities, APT28 Exploits Microsoft Office Zero-Day

Recorded Future InsiktFeb 24, 2026 High

Microsoft Office Security Feature Bypass Vulnerability (CVE-2026-21509)

NICS TaiwanFeb 5, 2026 High

CERT-EU Cyber Brief January 2026 – Espionage, Ransomware, and Critical Vulnerabilities

CERT-EU Threat IntelFeb 2, 2026 High

Microsoft Office Security Restriction Bypass Vulnerability (CVE-2026-21509)

GovCERT.HKJan 27, 2026

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