Advisory Details

February 16th, 2022

Linux Kernel io_uring Use-After-Free Privilege Escalation Vulnerability

ZDI-22-362
ZDI-CAN-14621

CVE ID
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 credentials in io_uring. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the kernel.

ADDITIONAL DETAILS Linux has issued an update to correct this vulnerability. More details can be found at:
https://github.com/torvalds/linux/commit/a30f895ad3239f45012e860d4f94c1a388b36d14
DISCLOSURE TIMELINE
  • 2021-08-20 - Vulnerability reported to vendor
  • 2022-02-16 - Coordinated public release of advisory
CREDIT Ryota Shiga(@Ga_ryo_) of Flatt Security
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