// For flags

CVE-2021-41270

CSV Injection in Symfony

Severity Score

6.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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 `@`.

Symfony/Serializer maneja la serialización y deserialización de estructuras de datos para Symfony, un framework PHP para aplicaciones web y de consola y un conjunto de componentes PHP reusables. Symfony versiones 4.1.0 anteriores a 4.4.35 y versiones 5.0.0 anteriores a 5.3.12, son vulnerables a una inyección de CSV, también se conoce como inyección de fórmulas. En Symfony 4.1, los mantenedores añadieron la opción "csv_escape_formulas" en el "CsvEncoder", para prefijar todas las celdas que empiezan con "=", "+", "-" o "@" con un tabulador "\t". Desde entonces, OWASP ha añadido 2 caracteres en esa lista: Tabulador (0x09) y retorno de Carro (0x0D). Esto hace que el anterior carácter de prefijo (Tab "\t") forme parte de los caracteres vulnerables, y OWASP sugiere usar la comilla simple "'" para prefijar el valor. A partir de las versiones 4.4.34 y 5.3.12, Symfony ahora sigue las recomendaciones de OWASP y usa la comilla simple "'" para prefijar las fórmulas y añadir el prefijo a las celdas que empiezan por "\t", "\r" así como "=", "+", "-" y "@"

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Low
Authentication
Single
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-09-15 CVE Reserved
  • 2021-11-24 CVE Published
  • 2023-10-11 EPSS Updated
  • 2024-08-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-1236: Improper Neutralization of Formula Elements in a CSV File
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Sensiolabs
Search vendor "Sensiolabs"
 Symfony
Search vendor "Sensiolabs" for product "Symfony"
 >= 4.1.0 < 4.4.35
Search vendor "Sensiolabs" for product "Symfony" and version " >= 4.1.0 < 4.4.35"
-
Affected
Sensiolabs
Search vendor "Sensiolabs"
 Symfony
Search vendor "Sensiolabs" for product "Symfony"
 >= 5.0.0 < 5.3.12
Search vendor "Sensiolabs" for product "Symfony" and version " >= 5.0.0 < 5.3.12"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 35
Search vendor "Fedoraproject" for product "Fedora" and version "35"
-
Affected