CVE-2023-35368

Unauthenticated code execution from adjacent networks

Published Aug 8, 2023 · Updated Aug 10, 2026

Improper input validation in Microsoft Exchange Server 2016 CU23 and 2019 CU12 through CU13 allows attackers to execute arbitrary code. Microsoft has not published the affected component, the untrusted input, or the validation operation that mishandles it. Exploitation requires adjacent-network access, and success compromises the Exchange server's data and execution environment.

CVSS severity8.8
High
EPSS probability2.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Microsoft Exchange Server 2016 CU23 and 2019 CU12 through CU13 allows attackers to execute arbitrary code. Microsoft has not published the affected component, the untrusted input, or the validation operation that mishandles it. Exploitation requires adjacent-network access, and success compromises the Exchange server's data and execution environment.

The record

CVE
CVE-2023-35368
Published
Aug 8, 2023
Updated
Aug 10, 2026
Vendor
Microsoft
Product
Microsoft Exchange Server 2019 Cumulative Update 12
Classifications
CWE-20, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 8, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=15.02.0 <15.02.1118.037

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Exchange Server 2019 Cumulative Update 12version=15.02.0 <15.02.1118.037
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 13version=15.02.0 <15.02.1258.025
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 23version=15.01.0 <15.01.2507.032

Published CVSS scores

8.8Microsoft CorporationCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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