A php7.3 security update has been released for Debian GNUL/Linux 10 to address multiple security issues.

DSA 4935-1: php7.3 security update

- -------------------------------------------------------------------------
Debian Security Advisory DSA-4935-1 security@debian.org
  https://www.debian.org/security/ Moritz Muehlenhoff
July 05, 2021   https://www.debian.org/security/faq
- -------------------------------------------------------------------------

Package : php7.3
CVE ID : CVE-2021-21704 CVE-2021-21705

Multiple security issues were found in PHP, a widely-used open source
general purpose scripting language which could result an SSRF bypass
of the FILTER_VALIDATE_URL check and denial of service or potentially
the execution of arbitrary code in the Firebird PDO.

For the stable distribution (buster), these problems have been fixed in
version 7.3.29-1~deb10u1.

We recommend that you upgrade your php7.3 packages.

For the detailed security status of php7.3 please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/php7.3

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/