Compressed request bodies can exhaust memory before extractor limits apply

Body extractors do not pass their size limits to the decompression layer. A small compressed request can therefore cause a large allocation before the extractor rejects the decoded body. A remote attacker can use this to exhaust memory or CPU resources and cause denial of service.

This affects applications that read compressed request bodies with the corresponding compression feature enabled.

Upgrade to actix-web 4.18.2 or later with actix-http 3.20.1 or later. As a workaround, reject compressed request bodies at a reverse proxy or in middleware before body extraction.