CVE-2026-54283

Name	CVE-2026-54283
Description	Starlette is a lightweight ASGI framework/toolkit. From 0.4.1 until 1.3.1, request.form() accepts max_fields and max_part_size to bound resource consumption while parsing form data. These limits are enforced for multipart/form-data, but silently ignored for application/x-www-form-urlencoded. An unauthenticated attacker can therefore send a urlencoded body with an arbitrarily large number of fields or an arbitrarily large field, even when the application configured limits it believed would apply. This vulnerability is fixed in 1.3.1.
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)

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
	bookworm (security)	0.26.1-1+deb12u1	vulnerable
	trixie	0.46.1-3+deb13u1	vulnerable
	trixie (security)	0.46.1-3+deb13u2	vulnerable
	forky, sid	1.1.0-1	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)

Notes

https://github.com/Kludex/starlette/security/advisories/GHSA-82w8-qh3p-5jfq
https://github.com/Kludex/starlette/pull/3329
Fixed by: https://github.com/Kludex/starlette/commit/dba1c4babc4f99ad2622bb913d87045775dda735 (1.3.1)