mixandClaude Opus 5.5
0cceb549cc
test / test (push) Canceled after 0s
The owner's decision (2026-10-16) on the security review's F1: a Sender: line - the sending agent's, shown beside From: as "on behalf of", and signed since 2.8.0 - was neither held to the login nor, before, signed: an application could write its own From: and Sender: ceo@bank.com under this server's signature. Now, when a message has one, it must be one address the application may send as, and at most one such line (RFC 5322 § 3.6); From: is judged first. The refusal is "550 5.7.1 Sender: <address> - <why>", a send-log row of reason "sender" (store.ReasonSender), tagged "wrong Sender"; the message page names the line. The log tailer recovers such a row from cleanup's line as it does a From: refusal (fromRefusalRe reads either). Help text as in the design commit d9d9af3; guide, architecture, security and CHANGELOG say it, security.md keeps Resent-From: (signed, not judged) as an accepted risk. Tests: TestSenderLineHeldToTheSameRule (own address, a name, another application's, a stranger's, two addresses, two lines, From: first), the recovery of a Sender: refusal line, the tag, the message page; e2e sender_check_holds_the_sender_line (own Sender: passes and is signed, another domain's refused at DATA and logged). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>