Exploited vulnerability · CISA KEV
Is CVE-2023-23397 exploited? Yes: in CISA KEV since 14 Mar 2023
Gociux · Microsoft Office · data: CISA KEV, CVE record, FIRST EPSS
Yes. CVE-2023-23397, Microsoft Office Outlook Privilege Escalation Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 14 Mar 2023, the day it was published. It affects Microsoft Office. If you run it, CISA's required action is: Apply updates per vendor instructions.
exploitedYesCISA KEV · 14 Mar 2023
ransomwareNot knownno confirmed use
EPSStop 1%among the most likely CVEs to be exploited
severity9.8CVSS 3.1 · critical
US federal due4 Apr 2023BOD 22-01 deadline
What it is
Microsoft Office Outlook contains a privilege escalation vulnerability that allows for a NTLM Relay attack against another service to authenticate as the user.
| Vendor | Microsoft (391 exploited CVEs in KEV) |
| Product | Office |
| Vulnerability | Microsoft Office Outlook Privilege Escalation Vulnerability |
| Weakness | CWE-294 |
| Published | 14 Mar 2023 |
| Added to KEV | 14 Mar 2023 |
| Reported by (CNA) | microsoft |
What to do
- Check whether you run it. Look for Office in your asset inventory, including appliances and cloud images. Stack check lists every exploited Microsoft CVE at once.
- Apply the fix. Apply updates per vendor instructions.
- If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 14 Mar 2023.
- Get told next time. Email alerts when CISA adds a CVE for Microsoft.
Other exploited CVEs in Office
- CVE-2026-124194: Microsoft Office Outlook Missing User Interaction for Potentially Unsafe Action Vulnerability (10 Nov 2026)
- CVE-2009-0238: Microsoft Office Remote Code Execution (14 Apr 2026)
- CVE-2026-21514: Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability (10 Feb 2026)
- CVE-2026-21509: Microsoft Office Security Feature Bypass Vulnerability (26 Jan 2026)
- CVE-2009-0556: Microsoft Office PowerPoint Code Injection Vulnerability (7 Jan 2026)
- CVE-2007-0671: Microsoft Office Excel Remote Code Execution Vulnerability (12 Aug 2025)
References
Questions
Is CVE-2023-23397 being exploited?
Yes. CISA added CVE-2023-23397 to the Known Exploited Vulnerabilities catalog on 14 Mar 2023, which means there is reliable evidence of exploitation in the wild.
Is CVE-2023-23397 used in ransomware attacks?
CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.
How do I fix CVE-2023-23397?
Apply updates per vendor instructions. Check Microsoft's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Office and watch it for signs of compromise.
Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in March 2023 · Microsoft scorecard · act-now radar.
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