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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| crossbario | autobahn-python | >= 26.7.1, < 26.10.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | python-autobahn | No fix yet | — |
| Ubuntu 26.04 LTS | python-autobahn | No fix yet | — |
| Ubuntu 24.04 LTS | python-autobahn | No fix yet | — |
| Ubuntu 22.04 LTS | python-autobahn | No fix yet | — |
| Ubuntu 20.04 LTS | python-autobahn | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | python-autobahn | No fix yet | — |
| Ubuntu 16.04 LTS | python-autobahn | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | autobahn | >= 26.7.1, < 26.10.1 | 26.10.1 | GHSA-pjh6-c8mg-3x7m |
References
- https://github.com/crossbario/autobahn-python/security/advisories/GHSA-pjh6-c8mg-3x7m
- https://github.com/crossbario/autobahn-python/pull/1987
- https://github.com/crossbario/autobahn-python/commit/a41442bbee4f6126a8ce1bb892840124c24d16f1
- https://github.com/crossbario/autobahn-python/releases/tag/v26_10_1