Due to an unfortunate oversight, Rails 4.2.11.2 has a missing constant error. To address this Rails 4.2.11.3 has been released.
The original announcement for CVE-2020-8163 has a follow-up message with an updated patch if you’re unable to use the gems.
Here are the shas:
$ sha256sum *-4.2.11.3.gem
229cd7da59bd26faf3e9d67a8285150e6eba6f63e077392b68d93b02a06cfd34 actionmailer-4.2.11.3.gem
67e84b5fcde0b2d885987a444646fb4d741926fd565565a336e73c5153e7a5a4 actionpack-4.2.11.3.gem
3be3f1ab60f518415da2fab994eac7d4ad869ea6b89762b7c1a9922e0756963e actionview-4.2.11.3.gem
cab80c01aa01e0856c506c9a1fc7e492ca5e93c45ac917f9ea3671f8c77016ae activejob-4.2.11.3.gem
97b94190b4a2c1ccfaa9727a445d2b157dac8378959c37df3b51a0aafb3967fc activemodel-4.2.11.3.gem
cd6c8445c0b4ee3c89ec382149c0e7d44148d179092f69d8ec333be1fc4efcba activerecord-4.2.11.3.gem
515015c5b8c7b35af33f5911c14248b06438c25fda60905965ba8d3c2237e372 activesupport-4.2.11.3.gem
7502ee83259abce924803052e34f3a9d072b01050e41e2ae94a22ddfd16d9686 rails-4.2.11.3.gem
f33ac1fc4e3dff3f35369caaf7ca21ace876637fabba9d05e512bfc06379c789 railties-4.2.11.3.gem
Apologies to anyone affected by this error.