This is a heads up. There is a recently identified minor security issue in Mailman 2.1.27 and earlier. This is not something that allows permanent compromise or information leak from your site, but is something that needs to be fixed. This issue has been given CVE ID CVE-2018-13796.
I plan to release Mailman 2.1.28 on 24 July, 2018 along with details of the issue and a patch to apply to earlier releases.
This is just notification of that plan for those that need to plan ahead.
Also, if you are a Mailman translator and you have any updates to your translation, please submit them in some form prior to 24 July so they can be incorporated in the release.