Race condition in Linux kernel - CVE-2019-6974

Vulnerability identifier: #VU17555

CSH Severity: Low

CVSS v4: 8.7 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2019-6974

CWE-ID: CWE-362

Exploitation vector: Adjecent network

Exploit availability: No public exploit available

The vulnerability allows an adjacent attacker to gain elevated privileges or cause a denial of service (DoS) condition.

The weakness exists due to exists due to a race condition that causes the kvm_ioctl_create_device function, as defined in the virt/kvm/kvm_main.c source code file of the affected software, to improperly handle reference counting. An adjacent attacker can access the system and execute an application that submits malicious input, trigger a use-after-free condition and cause a targeted guest virtual machine to crash, resulting in a DoS condition. In addition, a successful exploit could allow the attacker to gain elevated privileges on a targeted system. 

Linux kernel
Amazon Linux AMI
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for Power 9
Red Hat Enterprise Linux for IBM System z (Structure A)
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux EUS Compute Node
Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux Server - Extended Update Support
Opensuse
Fedora

kernel (Red Hat package)
kernel-alt (Red Hat package)
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
kernel-rt (Red Hat package)
kernel
kernel-headers
kernel-tools
Red Hat Virtualization Host

The vulnerability has been addressed in the versions 4.9.156, 4.14.99, 4.19.21, 4.20.8.

Linux kernel - addressed in versions 4.4.176, 4.9.156, 4.14.99, 4.19.21, 4.20.8
kernel (Red Hat package) - addressed in versions 3.10.0-693.62.1.el7, 3.10.0-862.44.2.el7, 3.10.0-957.12.1.el7
kernel-alt (Red Hat package) - update to 4.14.0-115.12.1.el7a
kernel-rt (Red Hat package) - update to 3.10.0-957.12.1.rt56.927.el7
kernel - addressed in versions 4.20.8-100.fc28, 4.20.8-200.fc29
kernel-headers - addressed in versions 4.20.8-100.fc28, 4.20.8-200.fc29
kernel-tools - addressed in versions 4.20.8-100.fc28, 4.20.8-200.fc29

• https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=cfa39381173d5f969daf43582c95ad679189cbc9
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.156
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.99
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.21
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.8
• https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.4.176

• OpenSUSE Linux update for the Linux Kernel
• Red Hat update for kernel-alt
• Red Hat 7.5 update for kernel
• Red Hat Enterprise Linux Server 7.4 update for kernel
• Amazon Linux AMI update for kernel
• Red Hat Enterprise Linux 7 update for kernel-rt
• Red Hat Enterprise Linux 7 update for kernel
• Fedora 29 update for kernel, kernel-headers, kernel-tools
• Fedora 28 update for kernel, kernel-headers, kernel-tools