A python3 security update has been released for CentOS 7.

CentOS-announce: CESA-2020:5010 Moderate CentOS 7 python3 Security Update

CentOS Errata and Security Advisory 2020:5010 Moderate

Upstream details at :   https://access.redhat.com/errata/RHSA-2020:5010

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

x86_64:
69b52b527f2581aac941a0d4fa71d1bce28da1b79f2f313b12818e1090892dfb python3-3.6.8-18.el7.i686.rpm
1bdade2f19c49a1f75262e570473159eba076e5147708897ef26211f4c3e6253 python3-3.6.8-18.el7.x86_64.rpm
e47652fa5e7642d21ed5f8769fe5f4fa1d3e7f416afe2b8f600aaf2ad97b5e27 python3-debug-3.6.8-18.el7.i686.rpm
849380b5dd59adac484f86c0be1242d6fe1a44e5e1ad0f83c18bf6a82a4f531f python3-debug-3.6.8-18.el7.x86_64.rpm
0bfce88e921ad0a5fd946306ecf24c9d04e2662eaeaf728d05dbcdc32010c8ea python3-devel-3.6.8-18.el7.i686.rpm
01da9776dbd5c2c0b5ee6d9e9020302a9007e6bf195079f25e6cf699c93e1dec python3-devel-3.6.8-18.el7.x86_64.rpm
8f060c38fbe87356d18b29d60da5dae1ab1bb783fbe9d75c1738ca0ab27b8ec6 python3-idle-3.6.8-18.el7.i686.rpm
577c5f15aa7fe917fc8073ef1e9b96c46ff667b05714023b580aa56ba79395cb python3-idle-3.6.8-18.el7.x86_64.rpm
9640c5a912cb29c8938076ba00b4a29313f55ccd7e684dbbc133c330b71ec3aa python3-libs-3.6.8-18.el7.i686.rpm
f9e0e769bfa29d7f3fba358e5524c7245c425336886a47e1697aaa57c199fd16 python3-libs-3.6.8-18.el7.x86_64.rpm
f5e54963c8d3735251b4501639c3af99731c36ad7de1884a62f8086d7546d5b1 python3-test-3.6.8-18.el7.i686.rpm
c837dad26046c4672910508d3f90d5dca273c22c3503ded2f75eed49602908af python3-test-3.6.8-18.el7.x86_64.rpm
49fee1d14c58251ceaf27e463d004b657ab809c483a44ab5c2bc0bf22a098086 python3-tkinter-3.6.8-18.el7.i686.rpm
4ad165c06922e2252a43f8ea8424a0e1ad01faa0b3cc0656d5e88a5bb3bc053f python3-tkinter-3.6.8-18.el7.x86_64.rpm

Source:
2cb6b01ee12e01a16a3fc211d4d7361f615ad3971c44fefdcf059f9e9b0a4a1e python3-3.6.8-18.el7.src.rpm