CVE-2026-116579

Name	CVE-2026-116579
Description	Autobahn Python is a WebSocket and WAMP implementation for Python that supports Twisted and asyncio. From 26.7.1 until 26.10.1, PerMessageBrotli.decompress_message_data in compress_brotli.py calls the Brotli decompressor without an output limit and checks maxMessagePayloadSize only after a complete frame has been inflated. An unauthenticated WebSocket client can send a small, highly compressed frame that allocates hundreds of MiB before rejection, causing memory-exhaustion denial of service on servers that enable the opt-in permessage-brotli feature through the compress extra. Deflate and bzip2 already enforce the remaining output budget and are outside this residual vulnerability. This issue is fixed in version 26.10.1.
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
python-autobahn (PTS)	bookworm	22.7.1+dfsg1-2	fixed
	trixie	23.1.2+dfsg1-2	fixed
	forky, sid	24.4.2+dfsg1-5	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
python-autobahn	source	(unstable)	(not affected)

Notes

- python-autobahn <not-affected> (Incomplete fix for CVE-2026-77528 not applied)
https://github.com/crossbario/autobahn-python/security/advisories/GHSA-pjh6-c8mg-3x7m
https://github.com/crossbario/autobahn-python/pull/1987
Fixed by: https://github.com/crossbario/autobahn-python/commit/a41442bbee4f6126a8ce1bb892840124c24d16f1 (v26_10_1)