CVE-2026-70279 Microsoft Exchange Server Spoofing Vulnerability
An attacker can perform spoofing attacks against Microsoft Exchange Server users via cross-site scripting vulnerabilities.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-70279?
CVE-2026-70279 is a critical cross-site scripting vulnerability in Microsoft Exchange Server 2016 Cumulative Update 23, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
Weakness: CWE-79
Which versions are affected by CVE-2026-70279?
How do I fix CVE-2026-70279?
No fix has been published for CVE-2026-70279 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-70279 being exploited?
There is no known exploitation of CVE-2026-70279 in the wild and no public exploit code.
Sources
Also known as GHSA-93hh-687q-gjhh.