CSV Injection in Symfony
CVE-2021-41270

6.5MEDIUM

Key Information:

Vendor

Symfony

Status
Symfony
Vendor
CVE Published:
24 November 2021

What is 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 @.

Affected Version(s)

symfony >= 4.1.0, < 4.4.35 < 4.1.0, 4.4.35

symfony >= 5.0.0, < 5.3.12 < 5.0.0, 5.3.12

References

https://github.com/symfony/symfony/pull/44243
x_refsource_MISC
https://github.com/symfony/symfony/releases/tag/v5.3.12
x_refsource_MISC
https://github.com/symfony/symfony/security/advisories/GH...
x_refsource_CONFIRM

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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CVE-2021-41270 : CSV Injection in Symfony