CVE-2026-70279 Microsoft Exchange Server - Stored XSS

Microsoft Exchange Server contains a stored XSS caused by improper neutralization of input during web page generation, letting unauthorized attackers perform spoofing over a network, exploit requires no special conditions.

CVSS base score 9.3 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.86% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Stored XSS
Impact
Stored XSS
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Published
13 October 2026
Updated
15 October 2026
Weakness
CWE-79

Vendor fix

Update to the latest version of Microsoft Exchange Server.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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