CVE-2021-34981

Name	CVE-2021-34981
Description	Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the CMTP module. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel. Was ZDI-CAN-11977.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	buster	4.19.249-2	fixed
	buster (security)	4.19.304-1	fixed
	bullseye	5.10.209-2	fixed
	bullseye (security)	5.10.216-1	fixed
	bookworm	6.1.76-1	fixed
	bookworm (security)	6.1.90-1	fixed
	sid, trixie	6.7.12-1	fixed

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

Package	Type	Release	Fixed Version
linux	source	stretch	4.9.272-1
linux	source	buster	4.19.194-1
linux	source	(unstable)	5.10.46-1

https://www.zerodayinitiative.com/advisories/ZDI-21-1223/
https://git.kernel.org/linus/3cfdf8fcaafa62a4123f92eb0f4a72650da3a479 (5.14-rc1)