Microsoft Exchange Server
CVE-2026-55005 — Microsoft Exchange Server Remote Code Execution Vulnerability
Executive Summary
Heap-based buffer overflow in Microsoft Exchange Server allows an authorized attacker to execute code over a network.
Overview
8.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.7
EPSS Score
0.00664
probability of exploitation in the next 30 days
0.48614 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) |
Important | Remote Code Execution | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 14 | 5103214 (Security Update) |
Important | Remote Code Execution | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 15 | 5103213 (Security Update) |
Important | Remote Code Execution | Yes |
| Microsoft Exchange Server Subscription Edition RTM | 5103212 (Security Update) |
Important | Remote Code Execution | Yes |
Patches
4 patches
| Article | Type | Restart |
|---|---|---|
5103215 |
Security Update | Yes |
5103214 |
Security Update | Yes |
5103213 |
Security Update | Yes |
5103212 |
Security Update | Yes |
Exploits & PoC
No public exploit or PoC has been linked for this CVE yet. When available, references are sourced from public repositories and may be unverified or non-functional — review carefully before use.
Detection Rules
No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.
Acknowledgments
kunlun Lab & GLM
References
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