Advisory Details

October 21st, 2021

Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability

ZDI-21-1223
ZDI-CAN-11977

CVE ID CVE-2021-34981
CVSS SCORE 7.5, AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
AFFECTED VENDORS Linux
AFFECTED PRODUCTS Kernel
VULNERABILITY DETAILS

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.

ADDITIONAL DETAILS

Fixed in version 5.10.42


DISCLOSURE TIMELINE
  • 2021-04-23 - Vulnerability reported to vendor
  • 2021-10-21 - Coordinated public release of advisory
CREDIT Ryota Shiga(@Ga_ryo_) of Flatt Security
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