CVE-2026-55040 | Microsoft SharePoint Server Security Feature Bypass Vulnerability

Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.

Published: 2026-07-14 Last update: 2026-07-15 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-55040 is rated Moderate Risk (53.3/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.68%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-55040

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-15 — 0.68% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-55040

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]

Weakness enumeration for CVE-2026-55040

GitHub Security Advisory for CVE-2026-55040

GHSA-grxw-7cvc-96rv · Severity: critical — Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a...

Affected software / configurations for CVE-2026-55040

Vendor Product Version Raw CPE
microsoft sharepoint_server < 16.0.19725.20434 cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:*
microsoft sharepoint_server 2016 cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:*
microsoft sharepoint_server 2019 cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*

References for CVE-2026-55040

cvelogic Threat Intelligence