# CVE-2026-65660 — Microsoft SharePoint Enterprise Server 2016

**CISA KEV**

> As of 2026-09-26, CVE-2026-65660 is a HIGH-severity vulnerability in Microsoft SharePoint Enterprise Server 2016, CVSS v3.1 8.8, EPSS 2.1% (80.9th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-09-25), with a US federal remediation deadline of 2026-09-28. Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-65660, most recently “CISA Adds Two Actively Exploited KEVs: SharePoint Code Injection (CVE-2026-65660) and Mikrotik RouterOS Auth Bypass (CVE-2026-67279)”.

**Last updated:** 2026-09-26

## What is CVE-2026-65660?

Improper control of generation of code ('code injection') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

The record classifies CVE-2026-65660 under weakness class [CWE-94](https://intel.threadlinqs.com/cwe/CWE-94). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 3 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 55 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 8.8 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **EPSS (FIRST):** 2.1% probability of exploitation in the next 30 days, higher than 80.9% of all scored CVEs
- **CISA KEV:** Listed since 2026-09-25, federal remediation deadline 2026-09-28
- **Threadlinqs priority:** 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- **Published:** 2026-08-11, last modified 2026-09-26

## Is CVE-2026-65660 being exploited?

CISA added CVE-2026-65660 to the Known Exploited Vulnerabilities catalog on 2026-09-25, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-09-28 under BOD 22-01. Weaponised exploit code for CVE-2026-65660 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 56 in the Threadlinqs vulnerability feed.

- [ShadowForge-Cyber/CVE-2026-65660-Poc](https://github.com/ShadowForge-Cyber/CVE-2026-65660-Poc) (github)
- [HORKimhab/CVE-2026-65660](https://github.com/HORKimhab/CVE-2026-65660) (github)

## 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-2026-65660

The record marks a vendor fix as available for CVE-2026-65660. Patch reference: [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65660](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65660). Vendor advisory: [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65660](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65660). Because CVE-2026-65660 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-09-28. 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-2026-65660

2 tracked threats in the Threadlinqs corpus reference CVE-2026-65660, either in the campaign’s CVE list or as an indicator on the campaign record.

- [CISA Adds Two Actively Exploited KEVs: SharePoint Code Injection (CVE-2026-65660) and Mikrotik RouterOS Auth Bypass (CVE-2026-67279)](https://intel.threadlinqs.com/threat/TL-2026-2669) — CRITICAL · 2026-09-26
- [CISA Adds Actively Exploited WSO2 API Manager and Adobe Commerce Flaws to KEV Catalog, Warns on SharePoint Code Injection](https://intel.threadlinqs.com/threat/TL-2026-2680) — CRITICAL · 2026-09-25

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-09-27. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [msrc.microsoft.com — vendor advisory](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65660)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-65660
Full detection coverage and IOCs for threats exploiting CVE-2026-65660 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp