Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/crossbario/autobahn-python/commit/a41442bbee4f6126a8ce1bb8928
- https://github.com/crossbario/autobahn-python/pull/1987
- https://github.com/crossbario/autobahn-python/releases/tag/v26_10_1
- https://github.com/crossbario/autobahn-python/security/advisories/GHSA-pjh6-c8mg
FAQ
What is CVE-2026-116579?
CVE-2026-116579 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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...
How severe is CVE-2026-116579?
CVE-2026-116579 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-116579?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.