CVE-2023-23397 — 365 Apps
CRITICALCVE-2023-23397 is a critical-severity (CVSS 9.8) Improper Input Validation vulnerability in microsoft 365 apps. 34 public exploit references exist, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.
Microsoft Outlook Elevation of Privilege Vulnerability
Exploitation Status
Actively exploited in the wild
- CISA’s SSVC triage classifies this CVE as under active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-23397.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2023-23397 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
Microsoft Outlook Elevation of Privilege Vulnerability
Affected Products
365 appsmicrosoftofficemicrosoftoffice long term servicing channelmicrosoftoutlookmicrosoftResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Microsoft Outlook Elevation of Privilege Vulnerability
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every microsoft 365 apps deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2023-23397 yet — track the microsoft 365 apps advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2023-23397 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.