The security documentation's last open item of panel-dkim-signing (the
owner's decision, 2026-10-16): go-milter v0.4.1 added every header of a
session to a map of its own, emptied only on ABORT, and handed it to
Headers - which no milter of the panel reads. Postfix bounds one header,
not their number, so a message of nothing but headers up to the message
size limit was held whole by the library in the sender check, the signer
and the journal milter on 465/587 and in the inbound journal milter on port
25, where strangers send; the signer's 1 MiB refusal came after it was all
in.
third_party/go-milter is v0.4.1 from the module cache (BSD 2-Clause,
LICENSE kept) with session.go changed: CodeHeader hands the header to
Header and keeps nothing, CodeEOH hands Headers an empty map. PATCHES.md
says what and why, and how to take a new upstream version. go.mod replaces
the module with it; the Dockerfile copies third_party before "go mod
download". TestTheLibraryKeepsNoHeaders holds it through the library's own
client over two messages of one connection. Comments, security.md (the
accepted risk becomes a note), development.md's library table, the plan and
CHANGELOG follow.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
