Hello everyone,
Recently, there was a problem with pmg that bothered me. When I receive an email with a compressed archive as an attachment, pmg may not be able to decompress it. If it fails the first time, the content will not be scanned and it will be released directly. Does anyone encounter the same problem?

Since my mail server is equipped with MailScanner, it can still block problematic attachments, but I want to leave this tool entirely to pmg.

The following screenshots show that when pmg received the email and tried to decompress and scan it, it no longer checked the contents of the compressed file after the first failure and directly released it to the mail host. I only found out that the compressed file contained .exe when I received a blocking notification from MailScanner.

Hello everyone,
We're experiencing the same issue—it would be great to get a response.

2026-04-08T15:15:50.378415+02:00 %mailrelay% pmg-smtp-filter[1672986]: 14123269D655065572D: new mail message-id=<2091793371.1595321.1775653530539.JavaMail.zimbra@sungeiwang.com>
2026-04-08T15:15:50.472673+02:00 %mailrelay% pmg-smtp-filter[1672986]: 14123269D655065572D: found archive 'Pedido de Cota-1.r00' (application/vnd.rar)
2026-04-08T15:15:50.507753+02:00 %mailrelay% pmg-smtp-filter[1672986]: 14123269D655065572D: unpack failed - child '1672994' failed: 512
2026-04-08T15:15:50.508390+02:00 %mailrelay% pmg-smtp-filter[1672986]: 14123269D655065572D: unpack archive 'Pedido de Cota-1.r00' done (35 ms)

We received a notification from the service provider that there was malware in the archive.

ArchiveFilter supports an undocumented content type:

proxmox/unreadable-archive

It can be added via:

pmgsh create /config/ruledb/what/<ID>/archivefilter \
--contenttype 'proxmox/unreadable-archive'

This allows quarantining only archives that PMG failed to unpack
(e.g. "unpack failed - child XXXX failed: 512"),
while allowing normal ZIP/RAR/7z archives