// For flags

CVE-2021-41252

Cross-site scripting (XSS) from writer field content in the site frontend

Severity Score

5.4
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Kirby is an open source file structured CMS ### Impact Kirby's writer field stores its formatted content as HTML code. Unlike with other field types, it is not possible to escape HTML special characters against cross-site scripting (XSS) attacks, otherwise the formatting would be lost. If the user is logged in to the Panel, a harmful script can for example trigger requests to Kirby's API with the permissions of the victim. Because the writer field did not securely sanitize its contents on save, it was possible to inject malicious HTML code into the content file by sending it to Kirby's API directly without using the Panel. This malicious HTML code would then be displayed on the site frontend and executed in the browsers of site visitors and logged in users who are browsing the site. Attackers must be in your group of authenticated Panel users in order to exploit this weakness. Users who do not make use of the writer field are not affected. This issue has been patched in Kirby 3.5.8 by sanitizing all writer field contents on the backend whenever the content is modified via Kirby's API. Please update to this or a later version to fix the vulnerability.

Kirby es un CMS estructurado por archivos de código abierto ### Impacto: El campo writer de Kirby almacena su contenido formateado como código HTML. A diferencia de otros tipos de campo, no es posible escapar los caracteres especiales de HTML contra ataques de tipo cross-site scripting (XSS), de lo contrario el formato se perdería. Si el usuario ha iniciado sesión en el Panel, un script dañino puede, por ejemplo, lanzar peticiones a la API de Kirby con los permisos de la víctima. Como el campo writer no saneaba su contenido de forma segura al guardarlo, era posible inyectar código HTML malicioso en el archivo de contenido al enviarlo a la API de Kirby directamente sin usar el Panel. Este código HTML malicioso se mostraría entonces en el frontend del sitio y sería ejecutado en los navegadores de visitantes del sitio y de usuarios registrados que estuvieran navegando por el sitio. Los atacantes deben estar en su grupo de usuarios autenticados del Panel para poder explotar esta debilidad. Los usuarios que no hacen uso del campo writer no están afectados. Este problema ha sido parcheado en Kirby versión 3.5.8 saneando todo el contenido del campo escritor en el backend siempre que el contenido sea modificado por medio de la API de Kirby. Por favor, actualice a esta versión o a una posterior para solucionar la vulnerabilidad

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
High
Authentication
Single
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-09-15 CVE Reserved
  • 2021-11-16 CVE Published
  • 2023-06-09 EPSS Updated
  • 2024-08-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Getkirby
Search vendor "Getkirby"
 Kirby
Search vendor "Getkirby" for product "Kirby"
 >= 3.5.0 <= 3.5.7.1
Search vendor "Getkirby" for product "Kirby" and version " >= 3.5.0 <= 3.5.7.1"
-
Affected