CVE-2020-16947

CVE-2020-16947 is a high-severity vulnerability in Microsoft 365 Apps with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 34% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-125.

Key facts

Description

<p>A remote code execution vulnerability exists in Microsoft Outlook software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the targeted user. If the targeted user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.</p> <p>Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Outlook software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.</p> <p>Note that where severity is indicated as Critical in the Affected Products table, the Preview Pane is an attack vector.</p> <p>The security update addresses the vulnerability by correcting how Outlook handles objects in memory.</p>

Frequently asked questions

What is CVE-2020-16947?
<p>A remote code execution vulnerability exists in Microsoft Outlook software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the targeted user. If the targeted user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.</p> <p>Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Outlook software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.</p> <p>Note that where severity is indicated as Critical in the Affected Products table, the Preview Pane is an attack vector.</p> <p>The security update addresses the vulnerability by correcting how Outlook handles objects in memory.</p>
How severe is CVE-2020-16947?
CVE-2020-16947 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-16947 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 34% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-16947?
CVE-2020-16947 primarily affects Microsoft 365 Apps. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-16947?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-16947 published?
CVE-2020-16947 was published on 2020-10-16 and last updated on 2026-06-17.

References

Affected products (3)

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