Mage OSS Ships an OAuth Bypass That Creates Sessions from Unrecognized Providers

Mage OSS, a data pipeline orchestration tool, contains a critical authentication bypass vulnerability tracked as CVE-2026-111823 . The flaw, identified in GHSA-93gm-r5p2-wxq7 , carries a CVSS score of 9.8. It affects all versions of the platform through 0.9.80. The vulnerability stems from a failure in the OAuth callback handler, which incorrectly manages error states during the authentication handshake. When the system encounters an unknown provider, it triggers an error condition but proceeds to initialize a session regardless, effectively granting authenticated access without valid credentials.

The technical failure is categorized under CWE-390: Detection of Error Condition Without Action . In practice, the Mage OAuth callback logic fails to terminate the request flow when an error is detected. Instead, the error handler inadvertently completes the session creation process. This allows an unauthenticated actor to bypass the intended identity verification steps entirely. Because Mage is used to orchestrate complex data pipelines and often manages sensitive credentials for services like Amazon S3, Snowflake, and Salesforce, this bypass provides a direct path to infrastructure-level access.

This incident marks the tenth occurrence of a trust-through-defaults failure in the last 21 days, a pattern detailed in our nine-layer synthesis published today. While incidents were confined to identity providers, authentication libraries, or proxy layers, this is the first time the pattern has surfaced within data infrastructure tooling. The shift suggests that the underlying assumptions regarding secure defaults are failing across a broader range of the software stack than previously observed.

Current intelligence on the vulnerability remains limited. There is no confirmed exploitation in the wild, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Reports regarding the availability of a proof-of-concept are currently conflicting; The Core Group references public exploit material, while Feedly’s aggregation reports no evidence of a public PoC. Organizations should treat the risk as high based on the CVSS severity, but avoid assuming active exploitation until further verification is provided.

The inclusion of data infrastructure in this sequence of failures is significant. Unlike identity providers, which are designed to handle authentication as a primary function, data tools like Mage often treat authentication as a secondary integration. This architectural difference may lead to less rigorous testing of edge cases in OAuth flows. When these tools handle ML workflows and high-privilege credentials, the impact of a bypass is amplified, as the tool itself becomes a central point of failure for the entire data pipeline.

This vulnerability follows a series of similar failures across the stack, including Keycloak masked-secret reuse (Post 131948), Better Auth OAuth state reuse (Post 132071), Frontegg SAML validation failure (Post 132087), Citrix NetScaler SAML patch issues (Post 132019), AD FS spoofing CVEs (Post 132106), Budibase OIDC invite hijacking (Post 132121), OAuth2 Proxy header bypass (Post 132161), Microsoft Entra CSP enforcement (Post 132185), and WorkOS SAML dual-view XML parsing gap (Post 132192). Each of these incidents highlights a recurring failure: the system trusted an assertion without verifying that the assertion means what the system assumed.

Remediation requires immediate action. The vulnerability is addressed in commit 76c4f46 , which corresponds to PRs #6204 and #6205 . Organizations running Mage OSS should update to a version beyond 0.9.80 immediately. Beyond patching, security teams should audit their Mage instances for any unauthorized session activity or unusual configuration changes that may have occurred since the vulnerability was introduced. Given the nature of the flaw, logs may not show traditional brute-force attempts, as the bypass allows for direct session creation without valid credentials.

The transition of this pattern into the data layer confirms that the trust-through-defaults issue is not isolated to identity-specific software. When developers integrate third-party authentication, the assumption that the library or framework will handle error states securely is often misplaced. Mage is not an identity provider. It is a data pipeline platform. That it produced the same class of failure as the nine identity-layer incidents before it suggests the problem is architectural, not domain-specific. Any component capable of creating an authenticated session is a potential target for bypass, regardless of its primary function in the stack.

Heath — Forkast T/I/S