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Vulnerabilities

Vulnerability · CVE-2023-23397

Microsoft Office Outlook Privilege Escalation Vulnerability

Published Mar 14, 2023 · catalog updated Jun 16, 2026 · Microsoft Office

Patch now

CVE-2023-23397 is in the CISA known-exploited catalog, due Apr 4, 2023. Confirm Microsoft Office against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
97.16%
Remediation
Remediation guidance
Affected products
cpe microsoft/365 apps · cpe microsoft/office · cpe microsoft/office long term servicing channel · cpe microsoft/outlook · vendor Microsoft Office

Microsoft Office Outlook contains a privilege escalation vulnerability that allows for a NTLM Relay attack against another service to authenticate as the user. Initial-access exploit intelligence.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe microsoft/365 appsversion unspecified
  • cpe microsoft/office2019
  • cpe microsoft/office long term servicing channel2021
  • cpe microsoft/outlook2013
  • cpe microsoft/outlook2016
  • vendor Microsoft Officeversion unspecified

How to fix CVE-2023-23397

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2023-23397 is in the CISA known-exploited catalog, due Apr 4, 2023. Confirm Microsoft Office against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with microsoft/office long term servicing channel 2021. Apply updates per vendor instructions.

What should an analyst verify?

CWE-20: Improper Input Validation; CWE-294. EPSS 97.16%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 14, 2023 · Catalog

    Detected

    Microsoft Office Outlook contains a privilege escalation vulnerability that allows for a NTLM Relay attack against another service to authenticate as the user.

  2. Mar 14, 2023 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Apr 4, 2023 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    Microsoft Office Outlook contains a privilege escalation vulnerability that allows for a NTLM Relay attack against another service to authenticate as the user.

Sources

  • CISA KEVConfirmed exploitationCVE-2023-23397

    Microsoft Office Outlook contains a privilege escalation vulnerability that allows for a NTLM Relay attack against another service to authenticate as the user.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2023-23397

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-23397

    30-day exploitation probability 97.2%

    first.org
  • NIST NVDVulnerability recordCVE-2023-23397

    Microsoft Outlook Elevation of Privilege Vulnerability

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2023-23397

    Microsoft Office Outlook contains a privilege escalation vulnerability that allows for a NTLM Relay attack against another service to authenticate as the user.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.