Malformed article causing 100% CPU & multiple apache instances

[RichH]

Znuny 6.4
CentOS Linux release 7.9.2009
MariaDB 5.5.68
Perl 5.16.3
O365 Mailboxes using OAuth2 for fetchmail.

Hi,

We've been having a strange problem in that when email tickets are opened from a particular customer our Znuny server goes to 100% CPU and runs 5-6 instances of apache. We have 4 processors on the server. One or more of the apache instances runs as high as 250% CPU. This gets really bad if I click on the first article in the ticket - i.e. the original email from the customer. When the ticket is closed the CPU usage drops back to normal. There are 2 tickets that have the same problem.

I've copied the flat files for these articles from the Znuny server to my own PC and ran anti-malware scans, which found nothing. I've viewed the flat files using Notepad+ and found that in the 'file-2', which is formatted in HTML, it is missing a </body> tag in both cases. it appears that the file never ends.

I've attached one of these files. Could you tell me how the file-2 is formed from the original email? It seems that this is an issue on the customer's email system, but we'd like to be able to explain it to them so they can fix it.

Thanks!