Exploited vulnerability · CISA KEV

Is CVE-2017-11774 exploited? Yes: in CISA KEV since 3 Nov 2021

Gociux · Microsoft Office · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2017-11774, Microsoft Office Outlook Security Feature Bypass Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 3 Nov 2021, 1482 days after it was published. It affects Microsoft Office. If you run it, CISA's required action is: Apply updates per vendor instructions.

exploitedYesCISA KEV · 3 Nov 2021

ransomwareNot knownno confirmed use

EPSStop 1%among the most likely CVEs to be exploited

severity7.8CVSS 3.1 · high

US federal due3 May 2022BOD 22-01 deadline

What it is

Microsoft Office Outlook contains a security feature bypass vulnerability due to improperly handling objects in memory. Successful exploitation allows an attacker to execute commands.

Vendor	Microsoft (391 exploited CVEs in KEV)
Product	Office
Vulnerability	Microsoft Office Outlook Security Feature Bypass Vulnerability
Weakness	CWE-119
Published	13 Oct 2017
Added to KEV	3 Nov 2021
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 13 Oct 2017.
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

nvd.nist.gov/vuln/detail/CVE-2017-11774

Questions

Is CVE-2017-11774 being exploited?

Yes. CISA added CVE-2017-11774 to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, which means there is reliable evidence of exploitation in the wild.

Is CVE-2017-11774 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-2017-11774?

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 November 2021 · Microsoft scorecard · act-now radar.

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