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.
History

Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Thu, 18 Jun 2026 04:45:00 +0000

Type Values Removed Values Added
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.
Title Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-17T19:31:45.487Z

Reserved: 2026-05-22T20:57:10.976Z

Link: CVE-2026-48818

cve-icon Vulnrichment

Updated: 2026-06-17T19:31:37.575Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-17T17:50:12Z

Links: CVE-2026-48818 - Bugzilla

cve-icon OpenCVE Enrichment

No data.