CVE-2026-21527 Microsoft Exchange Server Spoofing Vulnerability
An attacker can spoof critical information in the Microsoft Exchange Server user interface, potentially misleading users or bypassing security checks.
- 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-2026-21527?
CVE-2026-21527 is a medium-severity vulnerability in Microsoft Exchange Server, published on 10 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
Which versions are affected by CVE-2026-21527?
It affects 2 products.
Products include Microsoft Exchange Server, Microsoft Exchange Server Subscription Edition.
How do I fix CVE-2026-21527?
No fix has been published for CVE-2026-21527 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-21527 being exploited?
There is no known exploitation of CVE-2026-21527 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Exchange Server
- CVE-2024-21410 Microsoft Exchange Server Privilege Escalation
- CVE-2021-34473 Microsoft Exchange Server Remote Code Execution
- CVE-2021-26855 Microsoft Exchange Server Remote Code Execution
- CVE-2021-34523 Microsoft Exchange Server Privilege Escalation
- CVE-2023-21529 Microsoft Exchange Server Deserialization of Untrusted Data
Sources
Also known as GHSA-87gj-v6h3-c8p3.