From Cambridge University Press:

Cambridge University Press & Assessment has experienced a cybersecurity incident which has affected some of our systems. We take these matters very seriously and we took immediate precautionary action to minimise the impact of the incident on our systems. We have engaged external IT experts who are helping us understand the full scope of the incident.  

Some of our colleagues have faced technical disruption, including temporary loss of email access, as we continue to take a number of precautionary measures to keep our systems secure. We are making good progress in restoring access whilst prioritising safety over speed.

… there are several delays to be aware of:

Some parts of the publishing process are unaffected, including submission and peer review, but we are temporarily unable to publish new content on Cambridge Core.  We are working hard to address this soon 
We are currently unable to provide our normal set of publishing reports to institutions …


You may also check our website where we will be posting regular updates:
https://www.cambridge.org/news-and-insights/technical-incident