Vulnerability 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 Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Sensiolabs | Symfony | >= 4.1.0, < 4.4.35 |
| Fedoraproject | Fedora | 34 |
Related Weaknesses (CWE)
References
- https://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208PatchThird Party Advisory
- https://github.com/symfony/symfony/pull/44243PatchThird Party Advisory
- https://github.com/symfony/symfony/releases/tag/v5.3.12Release NotesThird Party Advisory
- https://github.com/symfony/symfony/security/advisories/GHSA-2xhg-w2g5-w95xPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208PatchThird Party Advisory
- https://github.com/symfony/symfony/pull/44243PatchThird Party Advisory
- https://github.com/symfony/symfony/releases/tag/v5.3.12Release NotesThird Party Advisory
- https://github.com/symfony/symfony/security/advisories/GHSA-2xhg-w2g5-w95xPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
FAQ
What is CVE-2021-41270?
CVE-2021-41270 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 befo...
How severe is CVE-2021-41270?
CVE-2021-41270 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-41270?
Check the references section above for vendor advisories and patch information. Affected products include: Sensiolabs Symfony, Fedoraproject Fedora.