CVE-2021-32707: Bypass of image blocking in Nextcloud Mail
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.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is CVE-2021-32707?
CVE-2021-32707 is a vulnerability in Nextcloud Mail prior to version 1.9.6 that allows images in emails to leak the read state.
How does CVE-2021-32707 affect Nextcloud Mail?
CVE-2021-32707 affects Nextcloud Mail versions prior to 1.9.6 by not rendering images in emails to prevent the leak of read states.
What is the severity of CVE-2021-32707?
The severity of CVE-2021-32707 is medium with a CVSS score of 4.3.
How can I fix CVE-2021-32707?
To fix CVE-2021-32707, you should update Nextcloud Mail to version 1.9.6 or later.
Are there any references for CVE-2021-32707?
References for CVE-2021-32707 include: [GitHub Pull Request](https://github.com/nextcloud/mail/pull/5189), [Nextcloud Security Advisories](https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xxp4-44xc-8crh), [HackerOne Report](https://hackerone.com/reports/1215251).