CVE-2026-62911 Microsoft Exchange Server Elevation of Privilege Vulnerability
An authorized attacker can elevate privileges via authentication bypass in Microsoft Exchange Server, requiring immediate patching.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-62911?
CVE-2026-62911 is a high-severity authentication bypass vulnerability in Microsoft Exchange Server, published on 11 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Authentication bypass by capture-replay in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Weakness: CWE-294
Which versions are affected by CVE-2026-62911?
It affects 2 products.
Products include Microsoft Exchange Server, Microsoft Exchange Server Subscription Edition.
How do I fix CVE-2026-62911?
No fix has been published for CVE-2026-62911 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-62911 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62911 exists.
Public exploit code: 3 proofs of concept on GitHub.
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-hjp7-hfwh-7664.