CVE-2021-41270 Information

Description

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 @.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Reference

https://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208a8 https://github.com/symfony/symfony/security/advisories/GHSA-2xhg-w2g5-w95x https://github.com/symfony/symfony/releases/tag/v5.3.12 https://github.com/symfony/symfony/pull/44243 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

NONE

Base Severity

6.5