Advisory Details

October 13th, 2021

Linux Kernel eBPF Type Confusion Privilege Escalation Vulnerability

ZDI-21-1148
ZDI-CAN-14689

CVE ID CVE-2021-34866
CVSS SCORE 8.8, AV:L/AC:L/PR:L/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 low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the handling of eBPF programs. The issue results from the lack of proper validation of user-supplied eBPF programs, which can result in a type confusion condition. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the kernel.

ADDITIONAL DETAILS

Fixed in version 5.13.14


DISCLOSURE TIMELINE
  • 2021-08-20 - Vulnerability reported to vendor
  • 2021-10-13 - Coordinated public release of advisory
CREDIT Ryota Shiga(@Ga_ryo_) of Flatt Security
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