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.comshare 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.
Weakness
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Starlette | Encode | * | 1.1.0 (excluding) |
| Red Hat AI Inference Server 3.3 | RedHat | rhaiis/vllm-spyre-rhel9:1782352919 | * |
| Red Hat AI Inference Server 3.3 | RedHat | rhaiis/vllm-rocm-rhel9:1782353093 | * |
| Red Hat AI Inference Server 3.3 | RedHat | rhaiis/vllm-cuda-rhel9:1782352847 | * |
| Starlette | Ubuntu | questing | * |
Related Attack Patterns
References
- https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5
- https://github.com/Kludex/starlette/pull/3287
- https://github.com/Kludex/starlette/releases/tag/1.1.0
- https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r
- https://access.redhat.com/errata/RHSA-2026:30087
- https://access.redhat.com/errata/RHSA-2026:30088
- https://access.redhat.com/errata/RHSA-2026:30089
- https://access.redhat.com/security/cve/CVE-2026-48818
- https://bugzilla.redhat.com/show_bug.cgi?id=2490020
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48818.json