CVE-2020-16944

CVE-2020-16944 is a high-severity vulnerability in Microsoft Sharepoint Enterprise Server with a CVSS 3.x base score of 8.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Description

<p>This vulnerability is caused when SharePoint Server does not properly sanitize a specially crafted request to an affected SharePoint server.</p> <p>An authenticated attacker could exploit this vulnerability by sending a specially crafted request to an affected SharePoint server. The attacker who successfully exploited this vulnerability could then perform cross-site scripting attacks on affected systems and run script in the security context of the current user. These attacks could allow the attacker to read content that the attacker is not authorized to read, use the victim's identity to take actions on the SharePoint site on behalf of the victim, such as change permissions, delete content, steal sensitive information (such as browser cookies) and inject malicious content in the browser of the victim.</p> <p>For this vulnerability to be exploited, a user must click a specially crafted URL that takes the user to a targeted SharePoint Web App site.</p> <p>In an email attack scenario, an attacker could exploit the vulnerability by sending an email message containing the specially crafted URL to the user of the targeted SharePoint Web App site and convincing the user to click the specially crafted URL.</p> <p>In a web-based attack scenario, an attacker would have to host a website that contains a specially crafted URL to the targeted SharePoint Web App site that is used to attempt to exploit these vulnerabilities. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the vulnerability. An attacker would have no way to force users to visit a specially crafted website. Instead, an attacker would have to convince them to visit the website, typically by getting them to click a link in an instant messenger or email message that takes them to the attacker's website, and then convince them to click the specially crafted URL.</p> <p>The security update addresses the vulnerability by helping to ensure that SharePoint Server properly sanitizes user web requests.</p>

Frequently asked questions

What is CVE-2020-16944?
<p>This vulnerability is caused when SharePoint Server does not properly sanitize a specially crafted request to an affected SharePoint server.</p> <p>An authenticated attacker could exploit this vulnerability by sending a specially crafted request to an affected SharePoint server. The attacker who successfully exploited this vulnerability could then perform cross-site scripting attacks on affected systems and run script in the security context of the current user. These attacks could allow the attacker to read content that the attacker is not authorized to read, use the victim's identity to take actions on the SharePoint site on behalf of the victim, such as change permissions, delete content, steal sensitive information (such as browser cookies) and inject malicious content in the browser of the victim.</p> <p>For this vulnerability to be exploited, a user must click a specially crafted URL that takes the user to a targeted SharePoint Web App site.</p> <p>In an email attack scenario, an attacker could exploit the vulnerability by sending an email message containing the specially crafted URL to the user of the targeted SharePoint Web App site and convincing the user to click the specially crafted URL.</p> <p>In a web-based attack scenario, an attacker would have to host a website that contains a specially crafted URL to the targeted SharePoint Web App site that is used to attempt to exploit these vulnerabilities. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the vulnerability. An attacker would have no way to force users to visit a specially crafted website. Instead, an attacker would have to convince them to visit the website, typically by getting them to click a link in an instant messenger or email message that takes them to the attacker's website, and then convince them to click the specially crafted URL.</p> <p>The security update addresses the vulnerability by helping to ensure that SharePoint Server properly sanitizes user web requests.</p>
How severe is CVE-2020-16944?
CVE-2020-16944 has a CVSS 3.x base score of 8.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-16944 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-16944?
CVE-2020-16944 primarily affects Microsoft Sharepoint Enterprise Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-16944?
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-2020-16944 published?
CVE-2020-16944 was published on 2020-10-16 and last updated on 2026-06-17.

References

Affected products (3)

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