CVE-2026-55021
HighCVSS 7.3Exploitation Probability (EPSS)
Low risk39th percentile - higher than 39% of all known CVEs
Summary
A cross-site scripting (XSS) vulnerability in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network. The flaw is due to improper neutralization of input during web page generation.
Risk Assessment
An attacker can inject malicious scripts, leading to session theft, display of fraudulent content, or account takeover, compromising data confidentiality and integrity within the organization.
Recommendation
Apply the security update provided by Microsoft for Microsoft Office SharePoint immediately. Additionally, implement input filtering and output encoding mechanisms in web applications.
Other vulnerabilities in Microsoft Office SharePoint
See all- CVE-2026-40368High
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
- CVE-2026-40357High
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
- CVE-2026-35439High
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
- CVE-2026-33112High
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
- CVE-2026-33110High
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
- CVE-2026-20951High
Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to execute code locally.
- CVE-2026-20947High
Improper neutralization of special elements used in an sql command ('sql injection') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
- CVE-2026-70306Critical
A cross-site scripting vulnerability in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.
- CVE-2026-70332Critical
Improper input neutralization during web page generation (cross-site scripting) in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.
- CVE-2026-55040CriticalActively exploited
A vulnerability in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over the network due to weak authentication.
Original NVD description (English source)
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.