Double Free in Linux kernel - CVE-2018-20961

Vulnerability identifier: #VU20899

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2018-20961

CWE-ID: CWE-415

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error within the f_midi_set_alt function of drivers/usb/gadget/function/f_midi.c in the f_midi driver. A local user can create and run a specially crafted application, trigger double free error and execute arbitrary code on the target system with elevated privileges.

Linux kernel
Slackware Linux
Ubuntu
linux (Ubuntu package)
linux-raspi2 (Ubuntu package)
linux-aws (Ubuntu package)
linux-kvm (Ubuntu package)
linux-snapdragon (Ubuntu package)

Install update from vendor's website.

Linux kernel - update to 4.16.4
linux (Ubuntu package) - update to 4.4.0-165.193
linux-raspi2 (Ubuntu package) - update to 4.4.0-1123.132
linux-aws (Ubuntu package) - update to 4.4.0-1095.106
linux-kvm (Ubuntu package) - update to 4.4.0-1059.66
linux-snapdragon (Ubuntu package) - update to 4.4.0-1127.135

• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.16.4
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7fafcfdf6377b18b2a726ea554d6e593ba44349f
• https://github.com/torvalds/linux/commit/7fafcfdf6377b18b2a726ea554d6e593ba44349f

• Slackware Linux update for kernel
• Ubuntu update for linux, linux-aws, linux-kvm and more