KEV Intelligence

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2023-23397

Microsoft Outlook Elevation of Privilege Vulnerability

Microsoft / Microsoft Office LTSC 2021 · affected before https://aka.ms/OfficeSecurityReleases

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Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
97.4%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2023-23397 is an unauthenticated Microsoft Outlook Elevation of Privilege Vulnerability.

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Microsoft / Microsoft Office LTSC 2021 affected before https://aka.ms/officesecurityreleases.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Microsoft Outlook Elevation of Privilege Vulnerability

Microsoft Outlook Elevation of Privilege Vulnerability

Vendor Product Affected Status
Microsoft Microsoft Office LTSC 2021 Before https://aka.ms/OfficeSecurityReleases Affected
Microsoft Microsoft Outlook 2016 Before 16.0.5387.1000 Affected
Microsoft Microsoft 365 Apps for Enterprise Before https://aka.ms/OfficeSecurityReleases Affected
Microsoft Microsoft Office 2019 Before https://aka.ms/OfficeSecurityReleases Affected
Microsoft Microsoft Outlook 2013 Service Pack 1 Before 15.0.5537.1000 Affected
View vendor advisory (opens in new tab)
Published
14 Mar 2023
Exploitation Reported
14 Mar 2023
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

microsoft cisa nessus_scanner

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 14 Mar 2023

Independent exploitation attestation added to the KEV Intelligence record.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
CISA First 2023-03-14 00:00 UTC
Tenable Blog 2026-06-02 14:20 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nessus https://www.tenable.com/plugins/nessus/172607 02 Jun 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

97.4%

Weaknesses

Improper Input Validation CWE-20

Recent mention · Tenable Blog

Inside the customer environment: Where threat actors, vulnerabilities, and exposed assets intersect

Tenable Research has developed a graph-based model linking 600+ threat groups to real-world customer exposures. It reveals which vulnerabilities sit at the intersection of severity, active exploitation, and organizational risk.Key takeawaysThe "patch everything" strategy is...

Read full advisory

Timeline

From disclosure to observed exploitation

  1. KEV confirmed by Tenable Blog

    Exploitation attested by an external source

  2. Nessus plugin available

    Scanner coverage available

  3. CVE published

    Vulnerability disclosed publicly

  4. Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  5. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2023-23397

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2023-23397",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.97408,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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