CVE-2026-102894

Received Received - Intake

SAML Authentication Bypass in GPUStack

Publication date: 2026-11-04

Last updated on: 2026-11-04

Assigner: GitHub, Inc.

Description

GPUStack is an open-source GPU cluster manager for AI model serving and GPU instance provisioning. From 0.7.1 until 2.2.2, the /auth/saml/callback endpoint decoded SAML XML, used its NameID and attributes to resolve or provision a user, and minted a gpustack_session JWT without calling OneLogin_Saml2_Auth.process_response to verify the signature, issuer, audience, destination, or time conditions. Any network client could submit an identity for an existing user, including an administrator, or provision a new non-administrator account, even when SAML was not configured. Response and Assertion identifiers were not consumed, so captured signed responses could also be replayed. This issue is fixed in version 2.2.2.

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Meta Information

Published

2026-11-04

Last Modified

2026-11-04

Generated

2026-11-05

AI Q&A

2026-11-05

EPSS Evaluated

N/A

NVD

CVE-2026-102894

EUVD

EUVD-2026-117125

Affected Vendors & Products

Vendor	Product	Version / Range
gpustack	gpustack	>= 0.7.1, < 2.2.2

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-294	A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
CWE-347	The product does not verify, or incorrectly verifies, the cryptographic signature for data.

Attack-Flow Graph

Executive Summary

GPUStack versions 0.7.1 to 2.2.1 had a flaw in the SAML authentication process. The /auth/saml/callback endpoint did not verify SAML response signatures, issuers, audience, destination, or time conditions. This allowed attackers to submit fake identities for existing users, including administrators, or create new non-admin accounts even without SAML configured. Replayed signed responses were also possible.

Detection Guidance

Check GPUStack logs for unusual SAML authentication attempts or unauthorized user provisioning. Inspect network traffic for requests to /auth/saml/callback with SAML responses. Verify if JWT tokens are minted without proper SAML signature validation.

Impact Analysis

An attacker could gain unauthorized access to your GPUStack system as any user, including administrators. They could create new accounts, escalate privileges, or replay stolen SAML responses to maintain access. This bypasses authentication entirely if SAML is enabled or even if it is not.

Compliance Impact

This vulnerability likely violates compliance requirements for access control and audit logging in GDPR and HIPAA. Unauthorized access risks data breaches, improper data handling, and failure to maintain integrity of authentication systems. Organizations using affected versions may face regulatory penalties.

Mitigation Strategies

Upgrade GPUStack to version 2.2.2 or later immediately. Disable SAML authentication if not in use. Review user accounts for unauthorized access or new non-admin accounts. Monitor for replayed SAML responses.

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