CVE-2026-48818
Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
Description
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.
INFO
Published Date :
June 17, 2026, 5:50 p.m.
Last Modified :
June 17, 2026, 5:50 p.m.
Remotely Exploit :
No
Source :
GitHub_M
Affected Products
The following products are affected by CVE-2026-48818
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update Starlette to version 1.1.0 or later.
- Configure follow_symlink=True if updating is not possible.
- Restrict network access for the service account.
- Monitor for suspicious outbound SMB connections.
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CVE-2026-48818 vulnerability anywhere in the article.