Race condition in Linux kernel - CVE-2020-11884

Vulnerability identifier: #VU28419

CSH Severity: Low

CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2020-11884

CWE-ID: CWE-362

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local authenticated user to execute arbitrary code.

In the Linux kernel through 5.6.7 on the s390 platform, code execution may occur because of a race condition, as demonstrated by code in enable_sacf_uaccess in arch/s390/lib/uaccess.c that fails to protect against a concurrent page table upgrade, aka CID-3f777e19d171. A crash could also occur.

Linux kernel
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat Enterprise Linux for Power, little endian
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat CodeReady Linux Builder for ARM 64
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux Server - AUS
Fedora
kernel (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

Install update from vendor's website.

Linux kernel - addressed in versions 4.19.119, 5.4.36, 5.6.8
kernel (Red Hat package) - addressed in versions 4.18.0-80.23.2.el8_0, 4.18.0-147.13.2.el8_1, 4.18.0-193.1.2.el8_2
kernel - addressed in versions 5.6.8-100.fc30, 5.6.8-200.fc31, 5.6.8-300.fc32

• https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.119
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.36
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.6.8

• Red Hat Enterprise Linux 8 update for kernel
• Red Hat Enterprise Linux 8 update for kernel
• Red Hat Enterprise Linux 8.1 Extended Update Support update for kernel
• Fedora 31 update for kernel
• Fedora 30 update for kernel
• Fedora 32 update for kernel