CPANEL-35877 and the death of cPanel

If you hosts using cPanel haven’t figured it out just yet, there’s a fun issue where customers routinely cannot send mail unless they repeatedly try until it works. The bug was introduced with the fix to the 21 exim vulnerabilities on May 04, 2021.

Today, July 06, 2021, this bug is still live in cPanel servers and users experience it to varying degrees seemingly at random. The bug is simply this:

“condition check lookup defer”

According to cPanel this has been noted to occur when a user hits email quota, and can sometimes be fixed by restarting Dovecot. None of this is true. It cannot be solved without a software patch, not even briefly. Any correlation with a fix is merely correlation with the randomness of the behavior to begin with.

At this time, cPanel is holding back a fix for version 98 with plans to backport it at that time. However, cPanel 98 is not even on their testing tier at this time. It’s release date is unknown, possibly far into the future. That’s two months so far that many, if not all, cPanel servers are broken. Due to the intermittent and random nature of it, customer complaints may not be plentiful, but the bug is there and has been confirmed on all of our cPanel servers at MXroute at this time.

In a year where cPanel has continually raised prices in an effort to extort their client base (“Would be a shame if you had to migrate…”) and shake them down for every penny, they’ve released a major bug in the usability of their platform which threatens to go unchecked for at least a quarter of a year.

This needs to be spread louder. Anyone considering the purchase of a cPanel license needs to be aware. Take your money elsewhere. I don’t know what they’re using it for, but it isn’t development.


To follow up on my reaction to this at MXroute:

It has been my determination that the random behavior generates less complaints than migration to a new platform. Working around cPanel to attempt to fix it myself is unacceptable given the pricing increases and the likelihood of being abandoned by their support for breaking their package management. My determination has been that the least evil resolution to this problem is to wait for cPanel to release a patch. I’ll do so, but with annoying volume.

Given the volume of complaints from my customers, I suspect many hosts have yet to even receive a complaint. A lot of customers take temporary errors with a grain of salt and stay quiet.

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I was starting to think I was going crazy. Not too many complaints on our end but shared hosting is something like under 1% our business/revenue. A few clusters of weird reporters here and there and I keep having to put these tickets on hold and feeling bad about deferring them. I can’t imagine how it must feel dealing with something like this when you’re running something like MXroute.

Really strange, given the other issues we’ve had with how the overlords at WebPros operate their monopoly I should have suspected it to be a bug.


I’ve seen it. I just know how you monitor these things and figured if you haven’t fixed it yet it’s because it’s not fixable.

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