---
id: 7287
title: "CVE-2026-55040: SharePoint Server Subscription Edition improper JWT validation lead to Arbitrary Account Login"
cve: CVE-2026-55040
source_domain: blog.viettelcybersecurity.com
source_url: "https://blog.viettelcybersecurity.com/sharepoint-cve-2026-55040/"
published_at: "2026-08-11T05:13:00Z"
tags: ["authentication-bypass", "microsoft", "sharepoint", "jwt", "spoofing", "cve-2026-55040"]
phying_url: "https://phying.com/item/7287"
lang: en
---

# CVE-2026-55040: SharePoint Server Subscription Edition improper JWT validation lead to Arbitrary Account Login

## Summary

CVE-2026-55040: SharePoint Server Subscription Edition's token handler skips JWT signature validation, letting attackers forge Bearer tokens and log in as arbitrary accounts, including site admins.

## Intelligence Metadata

- **Sources:** blog.viettelcybersecurity.com
- **CVE:** CVE-2026-55040
- **Published:** 2026-08-11T05:13:00Z
- **Original:** https://blog.viettelcybersecurity.com/sharepoint-cve-2026-55040/
- **Phying News:** https://phying.com/item/7287