Arch Linux Security Advisory ASA-202107-41

Severity: Low
Date : 2021-07-20
CVE-ID : CVE-2021-32707
Package : nextcloud-app-mail
Type : information disclosure
Remote : Yes
Link : https://security.archlinux.org/AVG-2145

Summary

The package nextcloud-app-mail before version 1.10.1-1 is vulnerable to
information disclosure.

Resolution

Upgrade to 1.10.1-1.

pacman -Syu “nextcloud-app-mail>=1.10.1-1”

The problem has been fixed upstream in version 1.10.1.

Workaround

None.

Description

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 background-image CSS
attribute. Note that the images were still passed through the Nextcloud
image proxy, and thus there was no IP leakage.

Impact

A remote attacker could disclose whether an email message has been read
by embedding a remote CSS background image.

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xxp4-44xc-8crh
https://hackerone.com/reports/1215251
https://github.com/nextcloud/mail/pull/5189
https://github.com/nextcloud/mail/commit/e54c2331f4b98cc39a5b3899c8ed1468dfc5cc30
https://security.archlinux.org/CVE-2021-32707