CVE-2026-21509 is a high severity vulnerability with a CVSS score of 7.8. Active exploits exist with no official patch available - immediate mitigation is required.
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Very low probability of exploitation
EPSS predicts the probability of exploitation in the next 30 days based on real-world threat data, complementing CVSS severity scores with actual risk assessment.
Microsoft Office contains a security feature bypass vulnerability in which reliance on untrusted inputs in a security decision in Microsoft Office could allow an unauthorized attacker to bypass a security feature locally.