What is the CVSS score of EUVD-2026-54312?

EUVD-2026-54312 has a CVSS 3.1 base score of 9.6 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N. EPSS exploitation probability: 0.4%.

Which versions of Microsoft Teams are affected by EUVD-2026-54312?

Microsoft Teams contains a critical privilege escalation vulnerability (CVE-2026-62896) that allows any authenticated user to escalate access and compromise confidentiality and integrity of…

How to fix or mitigate EUVD-2026-54312?

Within 24 hours, disable external federation and guest access in Microsoft Teams admin center, restrict Teams administrative access to essential personnel, and enable comprehensive audit logging. Within 7 days, deploy network segmentation isolating Teams infrastructure from critical business systems and implement real-time monitoring for privilege escalation attempts. Within 30 days, apply Microsoft's security patch for CVE-2026-62896 immediately upon vendor release and conduct a comprehensive audit of Teams authentication and access events from July 2026 forward to identify potential exploitation.

Microsoft Teams EUVD-2026-54312

| CVE-2026-62896 CRITICAL

Improper Authentication (CWE-287)

2026-08-07 secure@microsoft.com

GHSA-x274-p4gq-2363

Authentication Bypass Microsoft Teams

9.6

CVSS 3.1 · Vendor: microsoft

Severity by source

Vendor (microsoft) PRIMARY

9.6 CRITICAL

AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

ENISA EUVD

CRITICAL

qualitative

vuln.today AI

9.6 CRITICAL

Network-reachable authentication bypass needing a low-privilege foothold (PR:L) with no user interaction; scope changes across a security boundary yielding high confidentiality and integrity impact but no availability effect.

3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Analysis Generated

Aug 07, 2026 - 00:34 vuln.today

CVE Published

Aug 07, 2026 - 00:16 nvd

CRITICAL 9.6

DescriptionCVE.org

Improper authentication in Microsoft Teams allows an authorized attacker to elevate privileges over a network.

AnalysisAI

Privilege elevation in Microsoft Teams allows an authenticated attacker with low-level access to bypass authentication controls and gain higher privileges across a network boundary. The CVSS:3.1 vector (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H) shows the flaw is remotely reachable, requires only low existing privileges, needs no user interaction, and crosses a security scope to compromise confidentiality and integrity of resources beyond the initially authorized context. No public exploit identified at time of analysis, and the issue is not listed in CISA KEV, but the 9.6 base score reflects the low barrier to abuse once an attacker holds any authenticated Teams foothold.

Technical ContextAI

The vulnerability is classified as CWE-287 (Improper Authentication), meaning Teams fails to correctly verify the identity or authorization of a principal before granting access to a protected function or resource. Microsoft Teams is a widely deployed collaboration and communication platform spanning cloud service endpoints and desktop/web clients, so the authentication logic in question is likely a server-side or service-to-service authorization check rather than a local client control. The scope-change flag (S:C) in the CVSS vector indicates the exploited component and the impacted component differ - an attacker abusing the flawed authentication in one security authority can affect resources managed by another, which is characteristic of token, session, or tenant/identity-boundary weaknesses in cloud collaboration services.

RemediationAI

Patch available per vendor advisory - apply the fix referenced in Microsoft's MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62896; for cloud-served components Microsoft typically remediates server-side, while Teams desktop and web clients should be updated to the latest available build. No exact fix version was provided in the input, so confirm the specific patched version or service-side remediation status directly in the MSRC advisory. As compensating controls until updates are confirmed applied, enforce least-privilege on Teams accounts and app permissions to shrink the pool of low-privilege footholds an attacker could escalate from, require phishing-resistant MFA and conditional-access policies to make obtaining that initial authenticated foothold harder, and monitor Teams and Entra ID sign-in and privilege-change audit logs for anomalous authorization events - noting that tightened conditional-access policies may add friction for legitimate users and should be validated against business workflows.