What is the CVSS score of EUVD-2026-54324?

EUVD-2026-54324 has a CVSS 3.1 base score of 9.9 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.9%.

Which versions of Azure Service Bus are affected by EUVD-2026-54324?

Microsoft Azure Service Bus is affected by a critical remote code execution vulnerability (CVSS 9.9) that allows attackers with valid credentials to compromise the entire messaging service.

How to fix or mitigate EUVD-2026-54324?

Within 24 hours: Initiate critical incident response-contact Microsoft Support to confirm exposure status for your Service Bus namespaces and obtain patch availability timeline, then immediately audit production systems and sensitive workloads running on Service Bus. Within 7 days: Deploy comprehensive audit logging and establish advanced monitoring for all Service Bus instances to detect exploitation attempts; implement network restrictions using Azure Private Endpoints or IP whitelisting to limit access to authorized applications, and review and tighten role-based access control (RBAC) policies to enforce least-privilege access. Within 30 days: Upon Microsoft patch availability, execute coordinated patching across all affected Azure subscriptions and Service Bus instances; until patches are deployed, evaluate temporary migration of highest-value workflows to alternative messaging platforms to minimize exposure.

Azure Service Bus EUVD-2026-54324

| CVE-2026-50515 CRITICAL

Deserialization of Untrusted Data (CWE-502)

2026-08-07 secure@microsoft.com

GHSA-fm3h-q54v-rjrj

Deserialization Microsoft Azure Service Bus

9.9

CVSS 3.1 · Vendor: microsoft

Severity by source

Vendor (microsoft) PRIMARY

9.9 CRITICAL

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

ENISA EUVD

CRITICAL

qualitative

vuln.today AI

9.9 CRITICAL

Network-reachable deserialization needing only low-privilege authorized access (PR:L); code execution escapes the caller's authority (S:C) with full C/I/A impact.

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

4.0 AV:N/AC:L/AT:N/PR:L/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

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Aug 07, 2026 - 00:30 vuln.today

CVE Published

Aug 07, 2026 - 00:16 nvd

CRITICAL 9.9

DescriptionCVE.org

Deserialization of untrusted data in Azure Service Bus allows an authorized attacker to execute code over a network.

AnalysisAI

Remote code execution in Microsoft Azure Service Bus lets an already-authorized (PR:L) attacker send maliciously crafted serialized data that the service deserializes without validation (CWE-502), executing attacker-controlled code across the network. The scope-changed CVSS 9.9 rating reflects that code execution can break out of the caller's authorization boundary into the underlying managed-service host, threatening confidentiality, integrity, and availability of the messaging infrastructure. There is no public exploit identified at time of analysis, but the near-maximal severity and cloud-hosted, multi-tenant nature of the platform make this a high-priority issue.

Technical ContextAI

Azure Service Bus is Microsoft's fully managed enterprise message-broker (queues, topics/subscriptions, publish-subscribe) used to decouple applications and services. The root cause is CWE-502, deserialization of untrusted data: the service reconstructs objects from an untrusted byte stream (e.g. a message payload or control-plane input) without sufficient type restriction or validation, allowing an attacker to influence the object graph that gets instantiated. In .NET-based messaging stacks this class of flaw typically enables arbitrary type/gadget instantiation leading to code execution. No CPE strings were supplied; because Service Bus is a cloud service rather than shipped software, exact 'affected versions' map to the service backend Microsoft operates rather than a customer-installed build.

RemediationAI

Because Azure Service Bus is a Microsoft-operated cloud service, the primary remediation is server-side and applied by Microsoft; review https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50515 to confirm whether action is required and whether any client SDK update is recommended (Patch available per vendor advisory; no exact fix version was provided in the input). As compensating controls while validating status, tighten access to Service Bus namespaces by using least-privilege Shared Access Signature/Azure RBAC roles and rotating any over-scoped SAS keys so fewer identities meet the PR:L precondition, restrict network reachability with Private Endpoints/VNet service endpoints and IP firewall rules to block untrusted senders, and enable diagnostic logging and monitoring for anomalous message-processing errors - noting that Private Endpoint enforcement can break existing public-network clients and must be tested before enforcing.