What’s Vulnerable › Vulnerabilities

CVE-2020-1493: Microsoft Outlook Information Disclosure Vulnerability

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 7.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-08-17 · updated 2026-06-17
• Weakness: CWE-922

Description

An information disclosure vulnerability exists when attaching files to Outlook messages. This vulnerability could potentially allow users to share attached files such that they are accessible by anonymous users where they should be restricted to specific users. To exploit this vulnerability, an attacker would have to attach a file as a link to an email. The email could then be shared with individuals that should not have access to the files, ignoring the default organizational setting. The security update addresses the vulnerability by correcting how Outlook handles file attachment links.

Affected products

• Microsoft 365 Apps: all versions
• Microsoft Office: 2019
• Microsoft Outlook: 2010-sp2, 2013-sp1, 2016
• Microsoft 365 Apps: from 16.0.1 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Outlook 2010 Service Pack 2: from 13.0.0.0 before publication — fixed in publication
• Microsoft Outlook 2013 Service Pack 1: from 15.0.0.0 before publication — fixed in publication
• Microsoft Office: from 19.0.0 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Outlook 2016 for Mac: from 16.0.0.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases; Microsoft Outlook 2010 Service Pack 2 publication; Microsoft Outlook 2013 Service Pack 1 publication; Microsoft Office https://aka.ms/OfficeSecurityReleases; Microsoft Outlook 2016 for Mac publication. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/169960/Microsoft-Outlook-2019-16.0.12624.20424-Out-Of-Bounds-Read.html
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1493
• http://packetstormsecurity.com/files/169960/Microsoft-Outlook-2019-16.0.12624.20424-Out-Of-Bounds-Read.html
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1493

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