SMTP relay corrupts 8-bit message content #4

New Issue

2026-06-17T17:12:09+01:00

lyrathorpe commented

2026-06-17 17:12:09 +01:00

SMTPProxyHandler.send_message (proxy_server.py:349) does:

message = data.decode("utf-8", errors="replace")

errors="replace" destroys any non-UTF-8 byte, damaging 8-bit bodies and attachments. smtplib.sendmail accepts bytes directly.

Fix:

Pass the raw envelope.content bytes to smtp.sendmail without decoding.

Acceptance:

A message with non-UTF-8 / 8-bit content is relayed byte-for-byte.

SMTPProxyHandler.send_message (proxy_server.py:349) does: message = data.decode("utf-8", errors="replace") errors="replace" destroys any non-UTF-8 byte, damaging 8-bit bodies and attachments. smtplib.sendmail accepts bytes directly. Fix: - Pass the raw envelope.content bytes to smtp.sendmail without decoding. Acceptance: - A message with non-UTF-8 / 8-bit content is relayed byte-for-byte.

lyrathorpe added the bug label 2026-06-17 17:12:09 +01:00

lyrathorpe referenced this issue from a commit

2026-06-17 17:22:31 +01:00

fix: relay raw SMTP bytes without decoding

lyrathorpe referenced a pull request that will close this issue

2026-06-17 17:22:53 +01:00

Fix POP3/SMTP correctness and IMAP robustness #10

lyrathorpe closed this issue

2026-06-17 17:33:11 +01:00

lyrathorpe referenced this issue from a commit

2026-06-17 17:33:12 +01:00

Fix POP3/SMTP correctness and IMAP robustness (#10)