CVE-2026-116579: Autobahn Python: permessage-brotli inflates a whole frame before maxMessagePayloadSize is checked (incomplete fix of GHSA-hxp9-w8x3-p566)
permessage-brotli inflates each frame fully before checking maxMessagePayloadSize, so one 421-byte frame makes the server allocate about 545 MiB even with a 1 MiB message limit (brotli expands about 1,000,000:1). Any unauthenticated client can exhaust server memory this way on servers that enable permessage-brotli. This bypasses the GHSA-hxp9-w8x3-p566 fix.
References
- github.com/advisories/GHSA-pjh6-c8mg-3x7m
- github.com/crossbario/autobahn-python/commit/a41442bbee4f6126a8ce1bb892840124c24d16f1
- github.com/crossbario/autobahn-python/pull/1987
- github.com/crossbario/autobahn-python/releases/tag/v26_10_1
- github.com/crossbario/autobahn-python/security/advisories/GHSA-pjh6-c8mg-3x7m
- nvd.nist.gov/vuln/detail/CVE-2026-116579
Code Behaviors & Features
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