CVE Vulnerabilities

CVE-2021-41270

Improper Neutralization of Formula Elements in a CSV File

Published: Nov 24, 2021 | Modified: Nov 07, 2023
CVSS 3.x
N/A
Source:
NVD
CVSS 2.x
4 MEDIUM
AV:N/AC:L/Au:S/C:P/I:N/A:N
RedHat/V2
RedHat/V3
Ubuntu

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 @.

Weakness

The product saves user-provided information into a Comma-Separated Value (CSV) file, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as a command when the file is opened by a spreadsheet product.

Affected Software

Name Vendor Start Version End Version
Symfony Sensiolabs 4.1.0 (including) 4.4.35 (excluding)
Symfony Sensiolabs 5.0.0 (including) 5.3.12 (excluding)

Potential Mitigations

References