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Microsoft Entra ID CVE-2026-69836

| EUVDEUVD-2026-63693 CRITICAL
Deserialization of Untrusted Data (CWE-502)
2026-08-20 microsoft GHSA-v6wh-624g-vvmv
10.0
CVSS 3.1 · Vendor: microsoft
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Attack ChainAIDerived

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

  1. Access
    Reach network-facing Entra ID endpoint
  2. Delivery
    Craft malicious serialized payload
  3. Exploit
    Submit to deserialization handler
  4. Execution
    Trigger unsafe object deserialization
  5. Persist
    Execute arbitrary code in service context
  6. Impact
    Pivot across scope-changed identity resources

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A08:2025 - Software or Data Integrity Failures
ASVS 5.0
V1 - Encoding and Sanitization Safe deserialization, type allowlists
MITRE ATT&CK

2 techniques across 2 tactics: Execution, 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 CVSS vector is AV:N/AC:L/PR:N/UI:N, so no authentication, no user interaction, and no special client-side conditions are required - exploitation is unauthenticated and remote against a reachable Entra ID deserialization endpoint. The concrete prerequisite from the description is that the attacker must be able to deliver untrusted serialized data to a network-facing component that deserializes it (CWE-502). The main limiting factor is exposure and reachability of the vulnerable endpoint plus Microsoft's service-side patch state: because Entra ID is a vendor-operated cloud service, remediation may already be applied centrally, which would substantially constrain real-world exploitability regardless of the maximal CVSS score.

Impact

Every raw signal points to top-tier severity: the CVSS 3.1 vector AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H yields a perfect 10.0, meaning low-complexity, unauthenticated, no-interaction network exploitation with full impact and scope change. The offsetting nuance is that EPSS is not provided, the CVE is not in CISA KEV, and no proof-of-concept is referenced, so there is no evidence of active exploitation or automatable mass-scanning yet - this is currently a high-theoretical-severity issue rather than a confirmed in-the-wild campaign. Because Entra ID is a cloud service that Microsoft operates and patches centrally, real-world tenant exposure depends heavily on whether Microsoft has already remediated the service side; organizations should nonetheless treat any RCE in their identity provider as an emergency and verify the vendor advisory rather than assume automatic protection. Given that a compromise of the identity layer can cascade into every federated application, defenders should prioritize this immediately and confirm remediation status directly with Microsoft.

Exploit ScenarioDerived

An unauthenticated attacker crafts a malicious serialized payload and sends it over the network to an exposed Entra ID endpoint that deserializes the input, triggering execution of attacker-controlled code within the identity service context. Because no authentication or user interaction is required (PR:N/UI:N) and complexity is low, a single crafted request could suffice; with scope change, successful execution could reach resources beyond the initial component. No public proof-of-concept is referenced at time of analysis.

Act Now Prioritize within 24-48h. Why: In CISA KEV with patch available.
Exploited in the wild (CISA KEV) 1 PoC candidate (unverified) Patch available 1.4% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 20, 2026

Remote code execution in Microsoft Entra ID lets an unauthenticated network attacker run arbitrary code by submitting maliciously crafted serialized data that the service deserializes without validation (CWE-502). The CVSS 3.1 base score is a maximum 10.0 with a scope change, reflecting unauthenticated network reach and full compromise of confidentiality, integrity, and availability. There is no public exploit identified at time of analysis, and the issue is not listed in CISA KEV, but the combination of a cloud identity platform and PR:N/UI:N makes this an urgent-patch candidate.

RemediationAI

Patch available per vendor advisory: Microsoft has released a fix, and the primary action is to review and apply guidance in the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69836; no exact standalone fix version is published because Entra ID is a Microsoft-operated cloud service, so much of the remediation is applied service-side by Microsoft. Customers should confirm their tenant reflects the fixed service state, review Entra sign-in and audit logs for anomalous authentication or token issuance around and before the disclosure window, and rotate high-privilege credentials and application secrets if any compromise indicators appear. As compensating controls pending confirmation, tighten conditional access policies, enforce phishing-resistant MFA on privileged roles, and restrict/monitor privileged directory and application administration - noting these harden the environment but do not themselves close a deserialization flaw in the service, which only the vendor fix resolves.

Affected VersionsENISA

Microsoft Entra - (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 ID (formerly Azure Active Directory) is Microsoft's cloud identity and access management service that underpins authentication, single sign-on, and conditional access for Microsoft 365 and countless integrated applications. The root cause is CWE-502, deserialization of untrusted data: the service reconstructs objects from attacker-controlled serialized input without adequately validating type or content, allowing an attacker to influence object instantiation and reach code-execution gadgets. The affected CPE is cpe:2.3:a:microsoft:microsoft_entra:*:*:*:*:*:*:*:*, and the scope change (S:C) in the CVSS vector indicates the vulnerable component can affect resources beyond its own security authority - significant for a shared multi-tenant identity plane.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

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

Unauthenticated network deserialization RCE with no user interaction gives AV:N/AC:L/PR:N/UI:N; identity-plane compromise affecting other systems justifies S:C and full C:H/I:H/A:H.

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

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

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

Lifecycle Timeline

2
Added to CISA KEV
Aug 21, 2026 - 16:46 CISA
CVE Published
Aug 20, 2026 - 21:43 nvd
CRITICAL 10.0

DescriptionCVE.org

Deserialization of untrusted data in Microsoft Entra ID allows an unauthorized attacker to execute code over a network.

Latest POC

1 PoC candidate from github (unverified)

Sign in to open the public PoC links collected for this CVE.

Executive ViewAI

Why It Matters

Microsoft Entra ID, the identity platform that controls authentication and access for organizational cloud resources, is vulnerable to CRITICAL remote code execution (CVSS 10.0) exploitable by unauthenticated attackers. Successful exploitation would grant adversaries the ability to bypass all access controls and compromise the confidentiality, integrity, and availability of all downstream systems and data.

Business Impact: Severe
Compensating Controls

Apply vendor patch.

Threat Model

5 threats: Elevation of Privilege, Denial of Service, Tampering and 2 more

6-step attack chain with trust boundaries and controls

Full threat model - attack chain, trust boundaries, controls per stage and evidence - is part of the Pro and Business plans.

Threat Intelligence Overview

Threat Score
5.0/10
Composite threat intelligence
EPSS Score
1.4%
Top 30% exploitable
Prevalence
Ubiquitous
core cloud identity provider for Microsoft 365 and Azure tenants
Threat Intel
3
1 sources
Vendor Status
Publicly Disclosed:No
Exploited:Yes
Latest Software Release:N/A
Social Media
85
Sightings
Data Quality
9 sources
Confidence: High

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 Yes
Public POC Yes
EPSS 1.4%
Patch available Yes
Active threat Yes
Deciding rule
In CISA KEV with patch available
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
Out-of-Cycle
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
Very High
Technical Impact
Total

Priority Score

126
Low Medium High Critical
KEV: +50
EPSS: +1
CVSS: +50
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: +5

Attack Technique

Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.

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