CVE-2026-53524

Name	CVE-2026-53524
Description	WeeChat (Wee Enhanced Environment for Chat) is a free chat client. In versions 4.3.0 through 4.9.0, the WeeChat relay module's WebSocket permessage-deflate decompression function relay_websocket_inflate() has no upper bound on output size. An authenticated relay user can send a small compressed WebSocket frame (~100 bytes) that decompresses to gigabytes, exhausting all server memory and crashing the entire WeeChat process. The api protocol enables permessage-deflate and requires authentication before WebSocket upgrade. Version 4.9.1 patches the issue.
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
weechat (PTS)	bookworm	3.8-1	vulnerable
	trixie	4.6.3-1	vulnerable
	forky, sid	4.10.0-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
weechat	source	(unstable)	4.9.3-1

Notes

https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3
Fixed by: https://github.com/weechat/weechat/commit/35699ea8025e5bcd37cca2b1c22f041c38b8a624 (v4.9.1)
https://weechat.org/doc/weechat/security/WSA-2026-1/