Multiple security issues have been found in the Mozilla Firefox web browser, which could potentially result in the execution of arbitrary code, cross-site scripting or spoofing the origin of a download.

Debian follows the extended support releases (ESR) of Firefox. Support for the 68.x series has ended, so starting with this update we're now following the 78.x releases.

Between 68.x and 78.x, Firefox has seen a number of feature updates. For more information please refer to https://www.mozilla.org/en-US/firefox/78.0esr/releasenotes/

For Debian 9 stretch, these problems have been fixed in version 78.3.0esr-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/firefox-esr

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