// For flags

CVE-2021-32707

Bypass of image blocking in Nextcloud Mail

Severity Score

4.3
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Nextcloud Mail is a mail app for Nextcloud. In versions prior to 1.9.6, the Nextcloud Mail application does not, by default, render images in emails to not leak the read state. The privacy filter failed to filter images with a `background-image` CSS attribute. Note that the images were still passed through the Nextcloud image proxy, and thus there was no IP leakage. The issue was patched in version 1.9.6 and 1.10.0. No workarounds are known to exist.

Nextcloud Mail es una aplicación de correo para Nextcloud. En versiones anteriores a 1.9.6, la aplicación Nextcloud Mail no renderiza, por defecto, las imágenes en los correos electrónicos para no filtrar el estado de lectura. El filtro de privacidad produce un fallo en filtrar las imágenes con un atributo CSS "background-image". Nótese que las imágenes seguían pasando mediante el proxy de imágenes de Nextcloud, y por lo tanto no había ningún filtrado de IP. El problema fue parcheado en versiones 1.9.6 y 1.10.0. No se conoce ninguna solución

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Low
Authentication
Single
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-05-12 CVE Reserved
  • 2021-07-12 CVE Published
  • 2023-10-04 EPSS Updated
  • 2024-08-03 CVE Updated
  • 2024-08-03 First Exploit
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-20: Improper Input Validation
  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
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 Mail
Search vendor "Nextcloud" for product "Nextcloud Mail"
 < 1.9.6
Search vendor "Nextcloud" for product "Nextcloud Mail" and version " < 1.9.6"
-
Affected