Microsoft Exchange Server
CVE-2026-55008 — Microsoft Exchange Server Spoofing Vulnerability
Executive Summary
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.
Overview
9.6
CVSS CRITICAL
Critical
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
Required
SCOPE
Changed
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 8.3
EPSS Score
0.0085
probability of exploitation in the next 30 days
0.55001 percentile - updated 2026-08-14
View on FIRST.org
Affected Products
4 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Microsoft Exchange Server 2016 Cumulative Update 23 | 5103215 (Security Update) |
Critical | Spoofing | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 14 | 5103214 (Security Update) |
Critical | Spoofing | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 15 | 5103213 (Security Update) |
Critical | Spoofing | Yes |
| Microsoft Exchange Server Subscription Edition RTM | 5103212 (Security Update) |
Critical | Spoofing | Yes |
Patches
4 patches
| Article | Type | Restart |
|---|---|---|
5103215 |
Security Update | Yes |
5103214 |
Security Update | Yes |
5103213 |
Security Update | Yes |
5103212 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
Michael Maturi with Google
References
On This Page