CVE-2026-48818

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductEncode Starlette

PublishedJun 17, 2026

First seenJun 17, 2026

Weakness typeCWE-918Server-side request forgery (SSRF)

How to fix

Update

encode starlette1.1.0 or later
starlette1.1.0 or later

Vendor advisories

Affected products

Product	Affected versions	Fixed in
encode starlette	v < 1.1.0	1.1.0
starlettePyPI	v < 1.1.0	1.1.0

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