NULL pointer dereference in Linux kernel - CVE-2019-9213

Vulnerability identifier: #VU17910

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-2019-9213

CWE-ID: CWE-476

Exploitation vector: Local access

Exploit availability: Public exploit is available

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dreference error in expand_downwards() in mm/mmap.c that does not check for the mmap minimum address, which makes it easier for attackers to exploit kernel NULL pointer dereferences on non-SMAP platforms. This is related to a capability check for the wrong task. A local user can perform a denial of service (DoS) attack.

Linux kernel
Amazon Linux AMI
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for IBM System z (Structure A)
Red Hat Enterprise Linux for Power 9
Red Hat Enterprise Linux for Real Time for NFV
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
Red Hat Enterprise Linux for Real Time
Opensuse
Fedora

kernel-alt (Red Hat package)
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel
kernel-headers

Install update from vendor's website.

Linux kernel - addressed in versions 4.9.162, 4.14.105, 4.19.27, 4.20.14
kernel-alt (Red Hat package) - update to 4.14.0-115.7.1.el7a
kernel (Red Hat package) - update to 4.18.0-80.4.2.el8_0
kernel-rt (Red Hat package) - update to 4.18.0-80.4.2.rt9.152.el8_0
kernel - addressed in versions 4.20.14-100.fc28, 4.20.14-200.fc29
kernel-headers - addressed in versions 4.20.14-100.fc28, 4.20.14-200.fc29

• Exploit #5803 - Reliable Datagram Sockets (RDS) - rds_atomic_free_op NULL pointer dereference Privilege Escalation (Metasploit) (June 17, 2021)
• Exploit #1491 - Reliable Datagram Sockets (RDS) rds_atomic_free_op NULL pointer dereference Privilege Escalation (March 18, 2020)

• http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0a1d52994d440e21def1c2174932410b4f2a98a1
• https://bugs.chromium.org/p/project-zero/issues/detail?id=1792
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.105
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.27
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.14
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.162
• https://github.com/torvalds/linux/commit/0a1d52994d440e21def1c2174932410b4f2a98a1

• NULL pointer dereference in Linux kernel
• Amazon Linux AMI update for kernel
• Red Hat update for kernel-alt
• OpenSUSE Linux update for the Linux Kernel
• OpenSUSE Linux update for the Linux Kernel
• Red Hat Enterprise Linux 8 update for kernel
• Red Hat Enterprise Linux 8 update for kernel-rt
• Fedora 29 update for kernel, kernel-headers
• Fedora 28 update for kernel, kernel-headers