What is CVE-2017-11774?

CVE-2017-11774 is a high-severity vulnerability in Microsoft Outlook, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.8/10. Published 2017-10-13.

How severe is CVE-2017-11774?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2017-11774 known to be exploited?

Yes. CVE-2017-11774 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 9 public proof-of-concept repositories are indexed.

Buffer overflow in Microsoft Outlook

CVE-2017-11774

Microsoft Outlook 2010 SP2, Outlook 2013 SP1 and RT SP1, and Outlook 2016 allow an attacker to execute arbitrary commands, due to how Microsoft Office handles objects in memory, aka "Microsoft Outlook Security Feature Bypass Vulnerability."

Vulnerability class: Buffer Overflow

Published 2017-10-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.596 (99.1th percentile), scored 2026-10-19.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.596 · newest: 0.596 · change: 0.000

Affected products

Microsoft Outlook — versions 2010, 2013, 2016
Microsoft Corporation Outlook — versions Outlook 2016, Outlook 2013 SP1 and RT SP1, Microsoft Outlook 2010 SP2

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-03.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-11774 (Patch, Vendor Advisory)
www.securityfocus.com/bid/101098 (VDB Entry, Third Party Advisory, vdb-entry, Broken Link)
www.securitytracker.com/id/1039542 (VDB Entry, Third Party Advisory, vdb-entry, Broken Link)
sensepost.com/blog/2017/outlook-home-page-another-ruler-vector/ (Exploit)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2017-11774?: CVE-2017-11774 is a high-severity vulnerability in Microsoft Outlook, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.8/10. Published 2017-10-13.
How severe is CVE-2017-11774?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2017-11774 known to be exploited?: Yes. CVE-2017-11774 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 9 public proof-of-concept repositories are indexed.