CVE-2026-87696 Microsoft Exchange Server Elevation of Privilege Vulnerability
An authorized attacker can elevate privileges on Microsoft Exchange Server due to improper cryptographic signature verification.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-87696?
CVE-2026-87696 is a high-severity vulnerability in Microsoft Exchange Server, published on 13 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Improper verification of cryptographic signature in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Weakness: CWE-347
Which versions are affected by CVE-2026-87696?
It affects 2 products.
Products include Microsoft Exchange Server, Microsoft Exchange Server Subscription Edition.
How do I fix CVE-2026-87696?
No fix has been published for CVE-2026-87696 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-87696 being exploited?
There is no known exploitation of CVE-2026-87696 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-q352-99mq-9jqq.