High [CVE-2026-48818] SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
This high-severity Red Hat Linux advisory covers CVE-2026-48818 affecting Red Hat AI Inference Server 3.3.
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Summary
Starlette is a lightweight ASGI framework/toolkit. In versions 1.0.1 and earlier, StaticFiles on Windows is vulnerable to SSRF.
An UNC path such as \\attacker.com\share can cause os.path.realpath to initiate an outbound SMB connection before the path is rejected, exposing the service account’s NTLMv2 credentials for offline cracking or relay even though the HTTP response is only a 404.
The issue affects default follow_symlink=False deployments, including frameworks built on Starlette such as FastAPI; POSIX systems and follow_symlink=True are unaffected. The issue is fixed in 1.1.0.
A remote attacker can exploit this by providing a specially crafted Universal Naming Convention (UNC) path, which causes the system to initiate an outbound Server Message Block (SMB) connection. This action can expose the service account's NTLMv2 credentials, potentially leading to information disclosure or further attacks.
This Important flaw in Starlette's StaticFiles component, which allows for NTLMv2 credential theft via specially crafted UNC paths, does not affect Red Hat products. The vulnerability is specific to Windows operating systems, and the vulnerable code is not present in Red Hat's supported configurations.
Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N). Weakness: CWE-918.
Affected Red Hat products: Red Hat AI Inference Server 3.3.
- 1.0.1
Official advisory · high-confidence parse· fetched 16 days ago·verify at source
- 1.1.0
- rhaiis/vllm-spyre-rhel9:1782352919
- rhaiis/vllm-rocm-rhel9:1782353093
- rhaiis/vllm-cuda-rhel9:1782352847
- RHSA-2026:30087
- RHSA-2026:30088
- RHSA-2026:30089
Official advisory · high-confidence parse· fetched 16 days ago·verify at source
Mitigation checklist
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Official advisory · high-confidence parse· fetched 16 days ago·verify at source
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