Security · High impactFan score 44 · Tier B
GPUStack: SAML callback trusts an unverified SAMLResponse, allowing authentication bypass and account takeover (CVE-2026-102894)
The Brief
- GPUStack's SAML callback accepts a posted SAMLResponse without verifying it.
- The callback decodes the XML, reads NameID and attributes, resolves or provisions the user, and issues a gpustacksession JWT.
- The signature, issuer and audience checks in OneLoginSaml2Auth.processresponse() are never called, which enables authentication bypass and account takeover.
Why it matters
Anyone who can reach a GPUStack SAML callback may be able to log in as an existing user or create one, so operators running SAML login should treat the instance as exposed until it is patched.
Who’s affected
- GPUStack deployments using SAML login
- CVE-2026-102894
- #gpustack
- #saml
- #authentication
- #vulnerability
- #account-takeover
Affects gpustack. Impact The callback Base64-decodes the posted XML, reads NameID and attributes, resolves or provisions the user, and mints a gpustacksession JWT — but never calls OneLoginSaml2Auth.processresponse(), the step that verifies the signature, issuer, audience…
Timeline
GitHub Advisory Database published advisory GHSA-62m9-f875-rqw6 disclosing the vulnerability
GitHub Advisory Database
GPUStack: SAML callback trusts an unverified SAMLResponse, allowing authentication bypass and account takeover (CVE-2026-102894)