CVE-2021-32707 Bypass of image blocking in Nextcloud Mail

2021-07-1219:05:13

CWE-200

CWE-20

GitHub_M

www.cve.org

nextcloud mail

privacy filter

image blocking

css attribute

nextcloud image proxy

ip leakage

patched

vulnerability

CVSS3

4.3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

AI Score

4.8

Confidence

High

EPSS

0.001

Percentile

30.5%

JSON

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.

CNA Affected

[
  {
    "product": "security-advisories",
    "vendor": "nextcloud",
    "versions": [
      {
        "status": "affected",
        "version": "< 1.9.6"
      }
    ]
  }
]