# CVE-2026-20945 — Microsoft SharePoint Enterprise Server 2016

> As of 2026-09-25, CVE-2026-20945 is a MEDIUM-severity vulnerability in Microsoft SharePoint Enterprise Server 2016, CVSS v3.1 4.6, EPSS 19.0% (97.2th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-20945, most recently “Microsoft April 2026 Patch Tuesday — 163 CVEs / 88 Advisories (CVE-2026-32201 SharePoint Zero-Day Exploited In-The-Wild, CVE-2026-33825 Defender EoP Public PoC, CVE-2026-33824 IKE RCE CVSS 9.8, CVE-2026-33827 TCP/IP Wormable RCE)”.

**Last updated:** 2026-09-25

## What is CVE-2026-20945?

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.

The record classifies CVE-2026-20945 under weakness class [CWE-79](https://intel.threadlinqs.com/cwe/CWE-79). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs a user to take an action first. 3 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 183 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 4.6 — MEDIUM (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N`)
- **EPSS (FIRST):** 19.0% probability of exploitation in the next 30 days, higher than 97.2% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 6.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-04-14, last modified 2026-09-25

## Is CVE-2026-20945 being exploited?

It currently carries a trending score of 29 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Microsoft](https://intel.threadlinqs.com/vendors/microsoft): SharePoint Enterprise Server 2016, SharePoint Server 2019, SharePoint Server Subscription Edition

## How to fix CVE-2026-20945

The record marks a vendor fix as available for CVE-2026-20945. Vendor advisory: [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20945](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20945). Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

## Threat activity tracking CVE-2026-20945

1 tracked threat in the Threadlinqs corpus references CVE-2026-20945, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Microsoft April 2026 Patch Tuesday — 163 CVEs / 88 Advisories (CVE-2026-32201 SharePoint Zero-Day Exploited In-The-Wild, CVE-2026-33825 Defender EoP Public PoC, CVE-2026-33824 IKE RCE CVSS 9.8, CVE-2026-33827 TCP/IP Wormable RCE)](https://intel.threadlinqs.com/threat/TL-2026-0391) — CRITICAL · 2026-04-19

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [msrc.microsoft.com — vendor advisory](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20945)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-20945
Full detection coverage and IOCs for threats exploiting CVE-2026-20945 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp