CVE-2021-41270

Symfony/Serializer handles serializing and deserializing data structures
for Symfony, a PHP framework for web and console applications and a set of
reusable PHP components. Symfony versions 4.1.0 before 4.4.35 and versions
5.0.0 before 5.3.12 are vulnerable to CSV injection, also known as formula
injection. In Symfony 4.1, maintainers added the opt-in
csv_escape_formulas option in the CsvEncoder, to prefix all cells
starting with =, +, - or @ with a tab \t. Since then, OWASP added
2 chars in that list: Tab (0x09) and Carriage return (0x0D). This makes the
previous prefix char (Tab \t) part of the vulnerable characters, and
OWASP suggests using the single quote ' for prefixing the value. Starting
with versions 4.4.34 and 5.3.12, Symfony now follows the OWASP
recommendations and uses the single quote ' to prefix formulas and add
the prefix to cells starting by \t, \r as well as =, +, - and
@.