CVE-2021-32728

Name	CVE-2021-32728
Description	The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-4974-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
nextcloud-desktop (PTS)	buster (security), buster, buster (lts)	2.5.1-3+deb10u2	fixed
	bullseye (security), bullseye	3.1.1-2+deb11u1	fixed
	bookworm	3.7.3-1+deb12u1	fixed
	trixie	3.13.2-2	fixed
	sid	3.15.0-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
nextcloud-desktop	source	buster	2.5.1-3+deb10u2	DSA-4974-1
nextcloud-desktop	source	bullseye	3.1.1-2+deb11u1	DSA-4974-1
nextcloud-desktop	source	(unstable)	3.3.1-1

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5
https://github.com/nextcloud/desktop/pull/3338