Why "yum" command fails with segmentation fault in Red Hat Enterprise Linux 7 ?

Issue

• Some yum commands (like yum makecache fast) failed with segmentation fault.
• The machine is managed with subscription manager, and it's configured properly.
• Using a local proxy to connect CDN.
• It seems that yum command could establish the HTTPS connection with the proxy.
• The following is the output with export URLGRABBER_DEBUG=1,debug.txt.

> CONNECT cdn.redhat.com:443 HTTP/1.1
...
< HTTP/1.1 200 Connection established
<
* Proxy replied OK to CONNECT request
* warning: CURLOPT_CAPATH not a directory (/etc/rhsm/ca/redhat-uep.pem)
*   CAfile: /etc/rhsm/ca/redhat-uep.pem
  CApath: /etc/rhsm/ca/redhat-uep.pem
* NSS: client certificate from file
*       subject: CN=xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Segmentation fault