Information disclosure in Microsoft 365 Apps For Enterprise
CVE-2026-21260
Exposure of sensitive information to an unauthorized actor in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
Vulnerability class: Information Disclosure
EPSS: 0.001 (22.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C.
Affected products
- Microsoft 365 Apps For Enterprise — versions 16.0.1
- Microsoft Office 2019 — versions 19.0.0
- Microsoft Office Ltsc 2021 — versions 16.0.1
- Microsoft Office Ltsc 2024 — versions 16.0.0
- Microsoft Outlook 2016 — versions 16.0.0.0
- Microsoft Sharepoint Enterprise Server 2016 — versions 16.0.0
- Microsoft Sharepoint Server 2019 — versions 16.0.0
- Microsoft Sharepoint Server Subscription Edition — versions 16.0.0
Weakness classification (CWE)
References
- Microsoft Outlook Spoofing Vulnerability (vendor-advisory, patch)
Frequently asked questions
- What is CVE-2026-21260?
- CVE-2026-21260 is a high-severity vulnerability in Microsoft 365 Apps For Enterprise, classified under Information Disclosure. CVSS score: 7.5/10. Published 2026-02-10.
- How severe is CVE-2026-21260?
- High severity. CVSS v3 base score is 7.5 out of 10.