CVE-2026-116078

HTTP/2 request bodies made of 1-byte DATA frames amplify memory use in Bandit

HIGH

8.7

CVSS Score

Published: October 28, 2026 at 01:26 PM UTC

Updated: October 28, 2026 at 03:24 PM UTC

1 product affected across 1 vendorBandit

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Severity

HIGH8.7

Exploit prediction

EPSS 0.5%

Description

Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/2 request body reader of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory via a request body sent as many 1-byte DATA frames. do_read_data/5 in lib/bandit/http2/stream.ex keeps every DATA frame payload as its own list element until the read returns. The :length option of read_body/2 counts body bytes, not frames, so a body of 1-byte frames costs a list cell and a binary term per byte. Interleaving the frames across up to 500 concurrent streams per connection keeps each stream consuming its frames as they arrive; in the reporter's test, 100 streams held 25 to 40 MiB of stream process memory for 5 MB sent. Only routes whose Plug reads the request body are affected, which includes any route behind Plug.Parsers. This issue affects bandit: from 0.3.1 before 1.14.1.