What’s Vulnerable › Vulnerabilities

CVE-2025-21259: Microsoft Outlook Spoofing Vulnerability

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-02-11 · updated 2026-06-17
• Weakness: CWE-451

Description

Microsoft Outlook Spoofing Vulnerability

Affected products

• Microsoft Outlook: before 4.2501.1 — fixed in 4.2501.1
• Microsoft Outlook: from 1.0 before 4.2501.1 — fixed in 4.2501.1

How to fix

Upgrade to a fixed version: Microsoft Outlook 4.2501.1; Microsoft Outlook 4.2501.1. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21259

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