CVE-2026-123218: GPUStack authentication bypass via localhost spoofing

CVE-2026-123218 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2026-11-04

GPUStack is an open-source GPU cluster manager for AI model serving. Prior to version 2.2.0, the authentication system incorrectly trusted requests appearing to come from the local machine (127.0.0.1), even when they arrived from the network. An attacker could spoof a loopback origin by manipulating headers or positioning a reverse proxy, gaining unauthenticated administrative access to create API keys, modify models, and execute arbitrary code on GPU workers.

Technologies: GPUStack, gpustack (PyPI). Vendors: GPUStack, PyPI.

Quick answers

Is CVE-2026-123218 exploited in the wild?
Yes. CVE-2026-123218 is known to be exploited in the wild, first recorded on 9 November 2026. Treat it as urgent.
How severe is CVE-2026-123218?
Critical severity, with a CVSS score of 9.8, published 4 November 2026.
Which products and versions are affected?
GPUStack prior to 2.2.0; gpustack (PyPI) < 2.2.0, ECOSYSTEM:introduced=0,fixed=2.2.0.
Is there a fix for CVE-2026-123218?
Yes. gpustack (PyPI): upgrade to 2.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-123218 attacked?
It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-123218?
Check whether you run GPUStack or gpustack (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • gpustack (PyPI): upgrade to 2.2.0 or later
    pip install "gpustack>=2.2.0"

Technical details

The vulnerability exists in gpustack/api/auth.py where the get_current_user function granted administrator access to any request originating from 127.0.0.1 when force_auth_localhost was false (the default). The client_ip_getter function accepted both reverse-proxy peer addresses and client-supplied X-GPUStack-Real-IP headers that could report loopback IPs, allowing remote attackers to bypass authentication. This grants full administrative privileges including user and model management, API key creation, secret disclosure, and code execution via the POST /v2/inference-backends/from-yaml endpoint.

Affected products

  • GPUStack GPUStack prior to 2.2.0

Identifiers

  • CVE-2026-123218
  • CVE-2026-116779
  • CVE-2026-123158
  • CVE-2026-102895
  • GHSA-gj9m-f8ph-pmhr

Timeline

  • 2026-11-04: disclosed
  • 2026-05-19: exploited: Exploitation observed in the wild against 2.1.1 deployment prior to patch date

References

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