EUVD-2026-82598
GHSA-v78g-wqrm-wm64
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessReach Fabric endpoint over network
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DeliveryForge spoofed authentication/trust token
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ExploitService accepts spoofed identity
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ExecutionBypass authentication as privileged principal
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PersistCross scope boundary to other resources
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ImpactElevate privileges and access/alter data
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Anti-spoofing controls
MITRE ATT&CK
1 technique across 1 tactic: Defense Evasion The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | No special preconditions are stated in the description: exploitation is network-based, unauthenticated, and requires no user interaction (AV:N/AC:L/PR:N/UI:N) against Microsoft Fabric, meaning any attacker able to reach the service could attempt the spoof before remediation. The scope change (S:C) implies the bypass lets the attacker cross the initial authorization boundary to affect other resources or tenants. The principal LIMITING factor is that Microsoft Fabric is a Microsoft-operated cloud SaaS, so the fix is applied centrally by the vendor - customers cannot and need not patch, and the exposure window closed once Microsoft remediated. The description gives no configuration- or version-specific gating, so no non-default setting is required. |
| Impact | The vendor CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H = 10.0) describes a worst-case, remotely reachable, unauthenticated, no-interaction spoofing flaw with scope change and full CIA impact in Microsoft Fabric, Microsoft's multi-tenant cloud analytics SaaS. On paper this is maximum severity. However, several exploitation-signal fields are missing: there is no EPSS probability, no CISA KEV listing, no SSVC decision data, and no public POC - so 'no public exploit identified at time of analysis.' Critically, this is a cloud-hosted service that Microsoft remediates server-side; the single MSRC reference is an update-guide entry with no customer-installable patch, no affected version list, and no CPE. The practical upshot: the CVSS 10.0 reflects theoretical worst-case impact in a multi-tenant environment (where a scope-crossing spoof could reach other tenants' data), but because the flaw is fixed in Microsoft's infrastructure, there is typically no customer action and no lingering exposure once remediated. This is a 'high-CVSS but low residual customer-risk' situation from the tenant's perspective - the acute risk window was pre-remediation and controlled by Microsoft. No conflicting AV/PR signals were found: the network, unauthenticated framing is internally consistent with a spoofing bypass. Treat the 10.0 as an accurate pre-fix severity, not an ongoing patch obligation for customers. |
| Exploit ScenarioDerived | A remote, unauthenticated attacker crafts spoofed authentication material or forged identity/trust tokens and submits them to Microsoft Fabric over the network, causing the service to treat the request as a legitimate, higher-privileged principal. With the scope change (S:C), the attacker's assumed identity can reach resources or tenants beyond the initially compromised boundary, elevating privileges and exposing/modifying data. No public exploit code has been identified, and the flaw is remediated server-side by Microsoft. |
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Alert meAnalysisAIv1 – Sep 18, 2026
Authentication bypass by spoofing in Microsoft Fabric lets unauthenticated network attackers impersonate a trusted identity and elevate privileges, with a scope change indicating the bypass can cross the initial authorization boundary to affect resources or tenants beyond the attacker's own. Microsoft and independent assessment both score this CVSS 3.1 10.0 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H), reflecting full confidentiality, integrity, and availability impact on the affected multi-tenant analytics service. No public exploit code exists and there is no confirmed active exploitation (no CISA KEV listing) at time of analysis, and because Fabric is a Microsoft-operated SaaS, exposure depends on vendor-side remediation rather than customer patching.
RemediationAI
Because Microsoft Fabric is a vendor-operated cloud service, no customer patch is required or available for CVE-2026-69843 - Microsoft remediates the authentication/spoofing logic server-side and the MSRC update guide (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69843) is the authoritative record to monitor for the fix timeline. Note that patch availability for this issue is recorded as per the vendor advisory only; no customer-facing fix version is documented in the available data. While awaiting or confirming vendor remediation, apply these compensating controls with their trade-offs: enforce Microsoft Entra ID Conditional Access (phishing-resistant MFA, device compliance, location/IP restrictions) for all principals touching Fabric, accepting the added sign-in friction and support load; restrict tenant-level Fabric external-sharing and guest access settings to shrink the blast radius the scope change implies, at the cost of reduced cross-tenant collaboration; monitor Entra sign-in and unified audit logs plus Fabric activity logs for anomalous token issuance, unfamiliar principals, and cross-workspace or cross-capacity access patterns, understanding this is detection rather than prevention and generates alert volume; and apply least-privilege role assignments so a spoofed identity inherits as little as possible, which may slow legitimate administration. Network-level blocking of Fabric endpoints is generally impractical for organizations that depend on the service, so identity hardening and monitoring are the practical interim measures; there is no configuration toggle documented in the input data that disables the vulnerable authentication path.
Affected VersionsENISA
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The root cause is CWE-290 (Authentication Bypass by Spoofing), meaning the service accepts attacker-supplied identity or trust material as legitimate instead of verifying it against an authoritative source - for example a forged token, assertion, header, or trust relationship that Fabric's authentication layer treats as already-authenticated. Because this is a cloud SaaS authentication boundary rather than a memory-safety or injection flaw, the exploit path is about convincing Fabric's identity/authorization logic that the attacker is someone else, which then grants that identity's privileges. The CVSS 3.1 vector AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H is notable for the scope change (S:C): a successful spoof is not contained to the attacker's own security scope, so resources, workspaces, capacities, or other tenants could be impacted - the classic risk pattern for multi-tenant platforms. The only reference supplied is Microsoft's MSRC update guide; no CPE strings or version ranges were provided, consistent with a centrally hosted service where the vulnerable component is the Fabric service endpoint itself rather than a downloadable build. No user interaction and no privileges are required, so any party able to reach the Fabric service endpoints could attempt the spoof until the vendor applied its fix.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Description states unauthenticated network spoofing that elevates privileges with no interaction; CWE-290 spoofing bypass crossing a trust boundary justifies PR:N, UI:N and S:C, and a full identity bypass supports high CIA.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
DescriptionCVE.org
Authentication bypass by spoofing in Microsoft Fabric allows an unauthorized attacker to elevate privileges over a network.
Executive ViewAI
Microsoft Fabric, Microsoft's multi-tenant analytics platform, is affected by a critical authentication bypass (CVE-2026-69843) that allows unauthenticated network attackers to impersonate trusted identities and potentially cross tenant boundaries. Because Fabric is a vendor-operated SaaS with no customer patch available, organizations relying on it for analytics and data integration face a severe risk of unauthorized data access, manipulation, and service disruption. Leadership should prioritize immediate monitoring and access restrictions while pressing Microsoft for a remediation timeline.
No vendor-released patch identified at time of analysis; interim mitigations include strict access controls, conditional access policies, enhanced logging and monitoring for anomalous authentication, least privilege enforcement, network restrictions, and vendor engagement for accelerated remediation.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Exploit-DB