The answer we’ve got from CloudLinux is:

Later, up to 1.1-61 version, mod_lsapi ignores any error returned by Apache output filters. 
This was wrong behavior, particularly, it could lead to XSS vulnerability. 
In 1.1-62 it was fixed, and now mod_lsapi fails if output filters fail. 
This is exactly what happened in this case. 
It would be better to understand, why output filters failed, and fix this error.

Could you please check why output filters failed?

Problem/Motivation

After the latest mod_lsapi upgrade by CloudLinux, admin login is not function any longer.

When we login to our fresh installed instance shows the message:

The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator at -- to inform them of the time this error occurred, and the actions you performed just before this error.
More information about this error may be available in the server error log.

And from server's logs:
[Sat Dec 24 16:16:06.293327 2022] [lsapi:error] [pid --:tid --] [client IP:PORT] [host SITE_DOMAIN] ap_pass_brigade failed in read_from_backend''' function, referer: SITE_URL

Steps to reproduce

Install a Drupal 9.5.0 or 10.0.0 instance using recommended way (composer) on a server (cPanel, CloudLinux, MariaDB) with mod_lsapi 1.1-62.

OS: CloudLinux v7.9.0 STANDARD kvm
cPanel Version: 106.0.11

Login to Drupal instance.

Comments

ath.galanis created an issue. See original summary.

ath.galanis’s picture

ath.galanis commented
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ath.galanis’s picture

ath.galanis commented
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cilefen’s picture

cilefen commented

@ath.galanis The steps to reproduce specify CloudLinux, but CloudLinux is a commercial platform. Is there a way to reproduce the bug with open-source software?

ath.galanis’s picture

ath.galanis commented

Hi @cilefen, unfortunately the answer is I don't know! The only extra test that I made is to install a fresh Drupal instance locally too, but issue is not reproduced there.

ath.galanis’s picture

ath.galanis commented
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larowlan’s picture

larowlan
Location 🇦🇺🏝.au GMT+10
commented
Category: Bug report » Support request
Issue tags: +Bug Smash Initiative

Providing provider specific advice makes this a support request unless it can be traced to an issue in core
Reclassifying as such

esQmo’s picture

esQmo commented

Just had the same issue on all my drupal 9 sites since dec 18 or so: unable to use the site when logged in (only /admin/modules was accessible).
I was able to fix this issue by downgrading lsapi to 1.1.61. But cPanel could force update Isapi again and the issue would arise.

CarlosLopezES’s picture

CarlosLopezES commented

Hi,

We also have this problem. I've contacted CliudLinux:

Our developers are already aware of this issue and are working on fixing it as part of an internal task MODLS-952.

King regards,

Ibykos’s picture

Ibykos commented

Hello, I've found a workaround by disabling the Big Pipe module. I'm not able to tell if will help you guys, but for the time being it has fixed the issue for me. Happy holidays!

ath.galanis’s picture

ath.galanis commented

https://blog.cloudlinux.com/mod_lsapi-pro-gradual-rollout-paused

sneo’s picture

sneo commented

@Ibykos yep it "fix" the issue for now.
I struggle to find where the issue could come. Thx for the shortcut ^^

CarlosLopezES’s picture

CarlosLopezES commented

https://blog.cloudlinux.com/gradual-rollout-for-mod_lsapi-1.1-63-has-bee...

It's fixed now... or should be!

longwave’s picture

longwave
he/him
Primary language English
Location UK
commented
Status: Active » Fixed

Marking fixed as per the update in #13.

Status: Fixed » Closed (fixed)

Automatically closed - issue fixed for 2 weeks with no activity.