// For flags

CVE-2021-32802

Preview generation used third-party library not suited for user-generated content in Nextcloud server

Severity Score

9.8
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Nextcloud server is an open source, self hosted personal cloud. Nextcloud supports rendering image previews for user provided file content. For some image types, the Nextcloud server was invoking a third-party library that wasn't suited for untrusted user-supplied content. There are several security concerns with passing user-generated content to this library, such as Server-Side-Request-Forgery, file disclosure or potentially executing code on the system. The risk depends on your system configuration and the installed library version. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.1.0. These versions do not use this library anymore. As a workaround users may disable previews by setting `enable_previews` to `false` in `config.php`.

El servidor Nextcloud es una nube personal de código abierto y autoalojada. Nextcloud admite la representación de vistas previas de imágenes para el contenido de archivos proporcionados por el usuario. Para algunos tipos de imágenes, el servidor Nextcloud estaba invocando una biblioteca de terceros que no era adecuada para el contenido no confiable proporcionado por el usuario. Se presentan varios problemas de seguridad al pasar contenido generado por el usuario a esta biblioteca, como un ataque de tipo Server-Side-Request-Forgery, una divulgación de archivos o una posible ejecución de código en el sistema. El riesgo depende de la configuración del sistema y de la versión de la biblioteca instalada. Es recomendado actualizar el servidor Nextcloud a versión 20.0.12, 21.0.4 o 22.1.0. Estas versiones ya no usan esta biblioteca. Como solución alternativa, los usuarios pueden deshabilitar las vistas previas al ajustar "enable_previews" a "false" en "config.php"

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
Low
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-05-12 CVE Reserved
  • 2021-09-07 CVE Published
  • 2024-05-23 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-829: Inclusion of Functionality from Untrusted Control Sphere
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Nextcloud
Search vendor "Nextcloud"
 Nextcloud Server
Search vendor "Nextcloud" for product "Nextcloud Server"
 < 20.0.12
Search vendor "Nextcloud" for product "Nextcloud Server" and version " < 20.0.12"
-
Affected
Nextcloud
Search vendor "Nextcloud"
 Nextcloud Server
Search vendor "Nextcloud" for product "Nextcloud Server"
 >= 21.0.0 < 21.0.4
Search vendor "Nextcloud" for product "Nextcloud Server" and version " >= 21.0.0 < 21.0.4"
-
Affected
Nextcloud
Search vendor "Nextcloud"
 Nextcloud Server
Search vendor "Nextcloud" for product "Nextcloud Server"
 >= 22.0.0 < 22.1.0
Search vendor "Nextcloud" for product "Nextcloud Server" and version " >= 22.0.0 < 22.1.0"
-
Affected