CVE-2025-62727

Name	CVE-2025-62727
Description	Starlette is a lightweight ASGI framework/toolkit. Prior to 0.49.1 , an unauthenticated attacker can send a crafted HTTP Range header that triggers quadratic-time processing in Starlette's FileResponse Range parsing/merging logic. This enables CPU exhaustion per request, causing denial‑of‑service for endpoints serving files (e.g., StaticFiles or any use of FileResponse). This vulnerability is fixed in 0.49.1.
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)
Debian Bugs	1119662

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
starlette (PTS)	bullseye	0.14.1-1	vulnerable
	bookworm	0.26.1-1	vulnerable
	forky, sid, trixie	0.46.1-3	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
starlette	source	(unstable)	(unfixed)			1119662

Notes

https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8
Fixed by: https://github.com/Kludex/starlette/commit/4ea6e22b489ec388d6004cfbca52dd5b147127c5 (0.49.1)