MicrosoftCVE-2026-55040
Microsoft Office SharePoint: unauthorized attacker could bypass a security...
Critical9.1CVE-2026-55040 · Published Jul 14, 2026 · updated Aug 19, 2026
Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| Microsoft SharePoint Enterprise Server 2016 Product | >= 16.0.0, < 16.0.5561.1001 | 16.0.5561.1001 |
| Microsoft SharePoint Server 2019 Product | >= 16.0.0, < 16.0.10417.20175 | 16.0.10417.20175 |
| Microsoft SharePoint Server Subscription Edition Product | >= 16.0.0, < 16.0.19725.20434 | 16.0.19725.20434 |
Details and references
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Severity from
- the vendor (its own CVE record or advisory)
- Weakness
- CWE-1390
- www.cve.org/CVERecord?id=CVE-2026-55040
- nvd.nist.gov/vuln/detail/CVE-2026-55040
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040
- github.com/sfewer-r7/CVE-2026-55040
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55040
- www.rapid7.com/blog/post/ra-microsoft-sharepoint-jwt-token-authentication-bypass-cve-2026-55040/
More Microsoft advisories
All Microsoft| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Jul 14 | Secret exfiltration vulnerability | High | 1.128.1 |
| Jul 14 | Workspace Trust Security Feature Bypass Vulnerability | High | 1.128.1 |
| Jul 14 | Remote Code Execution Vulnerability | High | 1.128.1 |
| Jul 14 | Microsoft .NET 8.0: unsafe deserialization | High7.8 | 8.0.29+9 more |
| Jul 14 | Microsoft .NET 8.0: code injection | High7.8 | 8.0.29+10 more |
| Jul 14 | Microsoft .NET 10.0: resource exhaustion | High7.5 | 10.0.10+5 more |