CVE-2021-23993

Name	CVE-2021-23993
Description	An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent. If an attacker creates a crafted OpenPGP key with a subkey that has an invalid self signature, and the Thunderbird user imports the crafted key, then Thunderbird may try to use the invalid subkey, but the RNP library rejects it from being used, causing encryption to fail. This vulnerability affects Thunderbird < 78.9.1.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-2632-1, DSA-4897-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
thunderbird (PTS)	buster	1:91.12.0-1~deb10u1	fixed
	buster (security)	1:115.9.0-1~deb10u1	fixed
	bullseye	1:115.7.0-1~deb11u1	fixed
	bullseye (security)	1:115.9.0-1~deb11u1	fixed
	bookworm	1:115.7.0-1~deb12u1	fixed
	bookworm (security)	1:115.9.0-1~deb12u1	fixed
	sid	1:115.9.0-1	fixed

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

Package	Type	Release	Fixed Version	Origin
thunderbird	source	stretch	1:78.10.0-1~deb9u1	DLA-2632-1
thunderbird	source	buster	1:78.10.0-1~deb10u1	DSA-4897-1
thunderbird	source	(unstable)	1:78.10.0-1

https://www.mozilla.org/en-US/security/advisories/mfsa2021-13/#CVE-2021-23993