Debian: DSA-4646-1 Critical: ICU Integer Overflow DoS Threat

For the oldstable distribution (stretch), this problem has been fixed
in version 57.1-6+deb9u4.

For the stable distribution (buster), this problem has been fixed in
version 63.1-6+deb10u1.

We recommend that you upgrade your icu packages.

For the detailed security status of icu please refer to its security
tracker page at:
https://security-tracker.debian.org/tracker/source-package/icu

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/