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CRITICAL · CVSS 9.8 CISA Known Exploited Vulnerability

CVE-2023-23397

Microsoft Office Outlook Privilege Escalation Vulnerability

Microsoft Office

Microsoft Outlook Elevation of Privilege Vulnerability

CVSS
9.8
CRITICAL
EPSS
97.2%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
14 Mar 2023
CWE-20, CWE-294

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 14 March 2023. US federal agencies were required to remediate it by 4 April 2023.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 97.2%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

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

Frequently asked questions

Is CVE-2023-23397 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2023-23397.

What does CVE-2023-23397 affect?

CVE-2023-23397 affects Microsoft Office. Microsoft Outlook Elevation of Privilege Vulnerability

How severe is CVE-2023-23397?

CVE-2023-23397 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 97.2%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 4 April 2023.

How should organisations respond to CVE-2023-23397?

Apply the vendor patch for Microsoft Office as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.