CVE-2026-111101

CVE-2026-111101 · HTTP/1.1 chunked request bodies made of 1-byte chunks amplify memory use in Bandit

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Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory and CPU via a request body made of many 1-byte chunks. The chunked reader in lib/bandit/http1/socket.ex keeps every chunk as its own list cell and binary term until IO.iodata_to_binary/1 joins them, and nothing limits the number of chunks. The :length option of read_body/2 counts only data bytes, so tiny chunks cost far more memory than their payload: 48 MB of 1-byte chunks grew one handler process to about 500 MB and took about 6 s of CPU. The route does not need to read the body, because on keep-alive connections ensure_completed/1 drains unread bodies through the same reader. This issue affects bandit: from 0.1.0 before 1.14.0.

CVSS 8.7 · High · EPSS 0.6% · Fix available

Published

2026-10-26T13:31:48.184Z

Updated

2026-10-26T15:35:51.401Z

Stack: system

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