CVE-2026-3432

Critical

Published: 02 March 2026

Published

02 March 2026

Modified

06 March 2026

KEV Added

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Patch

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CVSS Score 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Score 0.0014 33.6th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-3432 is a critical-severity Missing Authorization (CWE-862) vulnerability in Sim Sim. Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 33.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

AC-3 Access Enforcement good match

prevent

AC-3 mandates enforcement of approved authorizations for access to sensitive resources like OAuth tokens, directly countering the bypass of authorization checks in the /api/auth/oauth/token endpoint.

SI-2 Flaw Remediation good match

prevent

SI-2 requires timely identification, reporting, and correction of flaws such as the authorization bypass, enabling patching to SimStudio 0.5.74 or later as recommended.

SI-10 Information Input Validation partial match

prevent

SI-10 requires validation of information inputs like credentialAccountUserId and providerId to prevent unauthorized parameter-driven bypasses of authorization logic.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1528 Steal Application Access Token Credential Access

Adversaries can steal application access tokens as a means of acquiring credentials to access remote systems and resources.

attack.mitre.org →

Why these techniques?

The vulnerability is an authorization bypass in a public-facing API endpoint (T1190: Exploit Public-Facing Application), directly enabling theft of OAuth access tokens for any user (T1528: Steal Application Access Token).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

On SimStudio version below to 0.5.74, the `/api/auth/oauth/token` endpoint contains a code path that bypasses all authorization checks when provided with `credentialAccountUserId` and `providerId` parameters. An unauthenticated attacker can retrieve OAuth access tokens for any user by supplying their user…

ID and a provider name, effectively stealing credentials to third-party services.

Deeper analysisAI

CVE-2026-3432 is a critical authorization bypass vulnerability (CWE-862) in SimStudio versions below 0.5.74, specifically within the `/api/auth/oauth/token` endpoint. This flaw enables a code path that skips all authorization checks when the `credentialAccountUserId` and `providerId` parameters are supplied, allowing unauthorized retrieval of sensitive OAuth data. The issue carries a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N), highlighting its high severity due to network accessibility, low complexity, and lack of prerequisites.

Unauthenticated attackers can exploit this vulnerability remotely by providing any target user's ID along with a provider name via the affected endpoint. Successful exploitation grants the attacker the victim's OAuth access tokens, enabling credential theft and subsequent unauthorized access to linked third-party services.

The Tenable research advisory (TRA-2026-13) at https://www.tenable.com/security/research/tra-2026-13 details mitigation strategies, including upgrading to SimStudio version 0.5.74 or later to address the bypass.