Update: WHMCS CURL Bug

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WHMCS has discovered a problem in an earlier EA4 Curl Package introduced on CentOS servers.


UPDATE: This is reportedly fixed in ea-libcurl-7.67.0-2.2.1, so it should no longer be necessary to downgrade.

Working versions:
* ea-libcurl-7.66.0-1.1.2.cpanel.x86_64
* ea-libcurl-7.67.0-2.2.1.cpanel.x86_64

Buggy version:

Per https://forums.cpanel.net/threads/cpanel-curl-update-breaks-whmcs-enom-module.663449/ it may be necessary to restart PHP-FPM to apply the changes to the running PHP binaries.


You may receive the error seen below when trying to accomplish certain activities on remote systems, like trying to register a domain via eNom, managing a domain, or other hosting activities related to the accounts on your server.

Registrar Error
CURL Error: 56 - OpenSSL SSL_read: Success

whmcs curl registrar error


According to the curl devs, this issue is caused by:

an increase in the sensitivity of OpenSSL's SSL_ERROR_SYSCALL error so that abrupt server closures are also considered errors.


Evidently, when a server does not send a recognized ‘protocol termination point’ (eg. a HTTP content length or a zero length chunk and empty trailer) it will cause an error if the connection is closed abruptly. The absence of a TLS termination point (eg. a close_notify alert) will highlight this problem and increase the chances of this error occurring. This concern can also affect additional versions of CURL which utilize API system calls.

The previous system update to cURL 7.67 in EasyApache 4 version 2019-11-20 includes changes which caused this problem. The issue has been identified by the cURL developers and will be addressed in upcoming updates.


In order to address this issue right now, reverting to a prior version of cURL (version 7.66) will resolve the error:

[root@host]# yum downgrade ea-libcurl ea-libcurl-devel

We should also note that the WHMCS technical support team is unable to assist with this issue as it is a result of an upstream bug in curl.

You can monitor this situation by visiting the following links for full details:

If you are experiencing problems addressing this issue, give us a call today at 800.580.4985, or open a chat or ticket with us to speak with one of our knowledgeable System admins!

Avatar for David Singer

About the Author: David Singer

I am a g33k, Linux blogger, developer, student, and former Tech Writer for Liquidweb.com. My passion for all things tech drives my hunt for all the coolz. I often need a vacation after I get back from vacation....

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