CVE-2026-21260 Microsoft Outlook Spoofing Vulnerability
An attacker can spoof information in Microsoft Outlook by exposing sensitive data to unauthorized actors over a network.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-21260?
CVE-2026-21260 is a high-severity vulnerability in Microsoft 365 Apps, published on 10 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Exposure of sensitive information to an unauthorized actor in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
Weakness: CWE-200
Which versions are affected by CVE-2026-21260?
It affects 5 products.
Products include Microsoft 365 Apps, Microsoft Office, Microsoft Office Long Term Servicing Channel, Microsoft Outlook, Microsoft Sharepoint Server.
How do I fix CVE-2026-21260?
No fix has been published for CVE-2026-21260 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-21260 being exploited?
There is no known exploitation of CVE-2026-21260 in the wild and no public exploit code.
Other vulnerabilities in Microsoft 365 Apps
- CVE-2024-21413 Microsoft Outlook Improper Input Validation
- CVE-2023-23397 Microsoft Office Outlook Privilege Escalation
- CVE-2024-38189 Microsoft Project Remote Code Execution Vulnerability
- CVE-2023-35311 Microsoft Outlook Security Feature Bypass
- CVE-2026-21514 Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision
Sources
Also known as GHSA-2pm9-6ww9-wqv9.