CVE-2026-20959

Sharepoint Server vulnerability

CVSS

4.6

EPSS

7.0%

EPSS pct

93th

Exploited

No known

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.

Affected vendor

Microsoft

Affected product

Sharepoint Server

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Weakness type (CWE)

CWE-79 — Cross-Site Scripting (XSS)

Published

2026-01-13

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring low privileges, user interaction. Successful exploitation leads to low impact to confidentiality, low impact to integrity.

Its EPSS score of 7.0% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 93% of all scored CVEs.

Check your external exposure to CVE-2026-20959

Confirm whether Microsoft Sharepoint Server is running on any internet-facing host or subdomain.
Match discovered service fingerprints against the version affected by CVE-2026-20959.
Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2026-20959

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2026-20959 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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