GHSA-x9ff-22gv-65f4: Echo: BodyDump can discard BodyLimit overflow errors for unknown-length requests

Echo v5’s BodyDump middleware captured a bounded prefix, drained the remaining request body while ignoring read errors, and then replaced the body with the captured prefix. With an outer BodyLimit, an unknown-length request such as an HTTP/1.1 chunked request, and a BodyDump capture limit below the BodyLimit threshold, an overflow detected during that drain could be discarded.

The handler could consequently process a truncated request and return success even though the original body exceeded the configured limit. This is a conditional size-policy bypass; no general authentication bypass, production data modification or denial of service is claimed. Known-length requests rejected before BodyDump runs are unaffected by this path.