Ubuntu: USN-4753-1 Important: Firefox ESR Security Update

A sandbox escape was found in the Mozilla Firefox web browser, which
could potentially result in the execution of arbitrary code if
combined with additional vulnerabilities.

For the stable distribution (stretch), this problem has been fixed in
version 60.7.2esr-1~deb9u1.

We recommend that you upgrade your firefox-esr packages.

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

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/