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CVE-2021-41270
MEDIUM · CVSS 6.5
EPSS exploitation probability: 0%
Published 2021-11-24T19:15:07.887 · Last modified 2026-06-17T04:08:12.617

Summary

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 recommendation

Affected products

sensiolabs — symfony

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.