Microsoft Word Untrusted Input Security Feature Bypass
Actively exploited in the wild. Patch or mitigate immediately — don't wait for a maintenance window.
An unauthenticated attacker, with local access to the host, if a user is tricked into opening a malicious file or link, can fully compromise the system — steal data, tamper with it and take it offline.
Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to bypass a security feature locally.
Inferred from the weakness type (CWE) and how the flaw is reached — the techniques an attacker would chain to exploit this. Real-world corroboration appears here as threat intel is folded in.
Corroborated threat activity referencing this CVE — with source and confidence, not inference.
Named threat actors and observed ATT&CK techniques appear here as intel feeds are folded in — the ATT&CK chain above stays inferred until then.
Generated by Wavense from the CVE record — an immediate mitigation and the permanent fix.
Users should be trained to exercise extreme caution when opening unsolicited or untrusted Microsoft Word documents, particularly those from unknown senders. Enforce strict macro security settings, disabling all macros or allowing only digitally signed and trusted ones. Additionally, ensure Microsoft Office's Protected View feature is fully enabled for all documents originating from the internet or untrusted sources.
The permanent resolution requires applying the security update provided by Microsoft specifically addressing CVE-2026-21514 for affected versions of Microsoft Office Word. Administrators should prioritize deploying this patch across all endpoints running vulnerable versions of Word to prevent exploitation. Regular patching cycles and prompt application of security updates are crucial for maintaining system integrity.
An attacker can exploit this vulnerability by providing maliciously crafted input to Microsoft Word, bypassing a critical security feature locally. This could enable the execution of arbitrary code, installation of malware, or unauthorized access to sensitive information within the compromised system. The potential business consequences include data theft, system disruption, and significant reputational damage.
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Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.