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Entra Application Proxy CVE-2026-97785

| EUVDEUVD-2026-108539 CRITICAL
Improper Authentication (CWE-287)
2026-10-22 microsoft GHSA-5vq4-h6h5-3gjg
10.0
CVSS 3.1 · NVD
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach exposed Entra App Proxy endpoint
  2. Delivery
    Send crafted authentication request
  3. Exploit
    Bypass improper authentication check
  4. Execution
    Elevate to authorized principal
  5. Impact
    Access published applications and data

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication mechanism validation
MITRE ATT&CK

2 techniques across 2 tactics: Defense Evasion, Initial Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

The limiting precondition is deployment-specific rather than configuration-toggle-specific: the target organization must actually be using Microsoft Entra Application Proxy (the connector-based service that publishes on-premises/internal applications for remote access), and the attacker must be able to reach that proxy endpoint over the network. Within that deployment, the CVSS vector indicates no further gating - PR:N/UI:N/AC:L means no authentication, no user interaction and low complexity against the service. The precise feature state, protocol or request that triggers the improper authentication is not described in the available sources, so beyond 'Application Proxy is in use and network-reachable' no additional configuration requirement can be confirmed. Organizations not using Entra Application Proxy are not exposed to this specific flaw.

Impact

All severity signals point the same direction: the supplied CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N) scores 10.0 - network-reachable, low attack complexity, no privileges and no user interaction, with a scope change and high confidentiality and integrity impact, consistent with an improper-authentication (CWE-287) privilege elevation in an identity broker. The vuln.today decision label is act_now, the product is core Microsoft identity infrastructure, and the fix is confirmed (RL:O, RC:C) and reported by Microsoft itself, so this is a genuine high priority rather than a high-CVSS-but-low-real-risk issue. That said, the exploitation-maturity metrics qualify the urgency: the input carries E:U (exploit code unproven), there is no CISA KEV listing and no EPSS score was provided, so there is no evidence of active or widespread exploitation at time of analysis - the priority is driven by severity and the criticality of the affected component, not by observed in-the-wild activity. No key signals conflict; the main gap is the absence of EPSS data, so the near-term exploitation probability cannot be quantified from the input.

Exploit ScenarioDerived

A remote, unauthenticated attacker who can reach an organization's Microsoft Entra Application Proxy endpoint sends a request that abuses the improper authentication check to be treated as an authorized principal, elevating privileges across the trust boundary and reaching applications published through the proxy. Because the flaw requires no credentials, no user interaction and low complexity, exploitation is straightforward for any attacker with network access to the exposed service. No public exploit identified at time of analysis (exploit code is marked unproven), so this remains a theoretical chain rather than a demonstrated one.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.6% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 22, 2026

Improper authentication in Microsoft Entra Application Proxy (formerly AAD App Proxy) allows an unauthenticated, remote attacker to elevate privileges across a trust boundary, with the supplied CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N) scoring 10.0 - no privileges, no user interaction and low complexity, with high confidentiality and integrity impact and a scope change. Exposure is deployment-specific: the target organization must actually run Application Proxy to publish internal applications for remote access, and the proxy endpoint must be reachable by the attacker; organizations not using the service are not exposed to this flaw. Microsoft is the reporting party and a vendor patch is available per the MSRC update guide, and the vuln.today decision label is act_now; no public exploit code or confirmed active exploitation was identified in the supplied data, although the trigger conditions themselves are not described in the available sources.

RemediationAI

Apply the vendor fix documented in the Microsoft Security Response Center update guide for CVE-2026-97785 (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97785); the governing patch status is 'Patch available per vendor advisory', and the supplied data does not name an exact fixed build, so confirm the applicable update for your tenant and connector version directly in the MSRC advisory before closing the item. Treat this as an act_now priority given the 10.0 CVSS vector and the unauthenticated, low-complexity path into published applications, and inventory which internal applications are currently exposed through Application Proxy so their owners can be notified. Where the update cannot be deployed immediately, the available compensating control follows from the assessed precondition of network reachability: restrict access to the Application Proxy endpoints to known trusted networks or source ranges (for example via conditional access, network controls or an allowlist) - the trade-off is that legitimate remote and mobile users outside those ranges lose access to the published applications until the restriction is lifted. Organizations that do not use Entra Application Proxy do not need to act on this specific flaw.

Affected VersionsENISA

Microsoft Entra application proxy - (version not specified)

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Microsoft Entra Application Proxy (historically Azure AD / AAD App Proxy) is the connector-based identity-brokering service that publishes on-premises or internal web applications to remote users, authenticating them against Entra ID and then relaying requests through a connector to the internal application. The flaw is classified as CWE-287 (Improper Authentication), meaning the service fails to correctly establish or verify the identity of a caller at some point in that brokering path, so a request that should be rejected is instead treated as legitimate - consistent with the assessed privilege elevation over the network. The scope-change metric (S:C) indicates the impact crosses from the proxy/identity layer into components that are assumed to be protected by it, which in this architecture means published backend applications and the identity context attached to them; confidentiality and integrity are rated high while availability is rated none. The supplied CPE entry (cpe:2.3:a:microsoft:microsoft_entra_application_proxy, version fields wildcarded) identifies the affected product without pinning a version range, and the precise feature state, protocol or request that triggers the authentication failure is not described in the available sources.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY CRITICAL
NVD 10.0 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
vuln.today AI 10.0 CRITICAL

Improper authentication allows unauthenticated network privilege elevation (AV:N/AC:L/PR:N/UI:N) crossing a trust boundary (S:C) with high confidentiality and integrity impact but no stated availability effect (A:N).

3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

DescriptionNVD

Improper authentication in AAD App Proxy allows an unauthorized attacker to elevate privileges over a network.

Executive ViewAI

Why It Matters

A critical authentication bypass in Microsoft Entra Application Proxy (CVSS 10.0) can allow an unauthenticated remote attacker to cross a trust boundary and gain high-impact access to internal applications published through the service. Leadership should care because organizations that use Entra Application Proxy to expose internal systems to remote users face potential unauthorized access to sensitive data and integrity compromise, with potential for lateral movement into internal networks.

Business Impact: Severe
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.6%
Top 52% exploitable
Prevalence
High
optional feature of the near-ubiquitous Microsoft Entra enterprise identity platform
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:N/A
Social Media
1
Sightings
Data Quality
4 sources
Confidence: Medium

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.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.6%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Out-of-Cycle
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Very High

Priority Score

51
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +50
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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