CVE-2023-50247

Name	CVE-2023-50247
Description	h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The QUIC stack (quicly), as used by H2O up to commit 43f86e5 (in version 2.3.0-beta and prior), is susceptible to a state exhaustion attack. When H2O is serving HTTP/3, a remote attacker can exploit this vulnerability to progressively increase the memory retained by the QUIC stack. This can eventually cause H2O to abort due to memory exhaustion. The vulnerability has been resolved in commit d67e81d03be12a9d53dc8271af6530f40164cd35. HTTP/1 and HTTP/2 are not affected by this vulnerability as they do not use QUIC. Administrators looking to mitigate this issue without upgrading can disable HTTP/3 support.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, 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
h2o (PTS)	buster (security), buster, buster (lts)	2.2.5+dfsg2-2+deb10u2	fixed
	bullseye	2.2.5+dfsg2-6	fixed
	bookworm	2.2.5+dfsg2-7	fixed
	sid, trixie	2.2.5+dfsg2-9	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
h2o	source	(unstable)	(not affected)

Notes

- h2o <not-affected> (Vulnerable code introduced later)
https://github.com/h2o/h2o/security/advisories/GHSA-2ch5-p59c-7mv6
Fixed by: https://github.com/h2o/h2o/commit/d67e81d03be12a9d53dc8271af6530f40164cd35