NULL pointer dereference in Linux kernel - CVE-2019-20054
Published: December 28, 2019
Vulnerability identifier: #VU23818
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2019-20054
CWE-ID: CWE-476
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error in the Linux kernel before 5.0.6 in drop_sysctl_table() in fs/proc/proc_sysctl.c, related to put_links, aka CID-23da9588037e. A local user can perform a denial of service (DoS) attack.
Affected software
Linux kernel
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power 9
Red Hat Enterprise Linux for IBM System z (Structure A)
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel-alt (Red Hat package)
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power 9
Red Hat Enterprise Linux for IBM System z (Structure A)
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel-alt (Red Hat package)
How to mitigate CVE-2019-20054
Install update from vendor's website.
Linux kernel - update to 5.0.6
kernel (Red Hat package) - addressed in versions 3.10.0-1160.el7, 4.18.0-240.el8
kernel-rt (Red Hat package) - update to 3.10.0-1160.rt56.1131.el7
kernel-alt (Red Hat package) - update to 4.14.0-115.19.1.el7a
kernel (Red Hat package) - addressed in versions 3.10.0-1160.el7, 4.18.0-240.el8
kernel-rt (Red Hat package) - update to 3.10.0-1160.rt56.1131.el7
kernel-alt (Red Hat package) - update to 4.14.0-115.19.1.el7a
External References
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.11
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.6
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=23da9588037ecdd4901db76a5b79a42b529c4ec3
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=89189557b47b35683a27c80ee78aef18248eefb4