CVE-2026-48818

Name	CVE-2026-48818
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
starlette (PTS)	bullseye	0.14.1-1	fixed
	bookworm	0.26.1-1	fixed
	bookworm (security)	0.26.1-1+deb12u1	fixed
	trixie	0.46.1-3+deb13u1	fixed
	trixie (security)	0.46.1-3+deb13u2	fixed
	forky, sid	1.1.0-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
starlette	source	(unstable)	(not affected)

Notes

- starlette <not-affected> (Only affects Starlette on Windows)
https://github.com/Kludex/starlette/security/advisories/GHSA-wqp7-x3pw-xc5r
https://github.com/Kludex/starlette/pull/3287
Fixed by: https://github.com/Kludex/starlette/commit/fd53168a7767b6b55ba5af787fd88f49e33cabc5 (1.1.0)