NULL pointer dereference in Linux kernel - CVE-2019-19227

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Main Vulnerability Database Vulnerabilities #VU30584

NULL pointer dereference in Linux kernel - CVE-2019-19227

Published: November 22, 2019 / Updated: July 17, 2020


Vulnerability identifier: #VU30584
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2019-19227
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in the AppleTalk subsystem in the Linux kernel before 5.1, there is a potential NULL pointer dereference because register_snap_client may return NULL. This will lead to denial of service in net/appletalk/aarp.c and net/appletalk/ddp.c, as demonstrated by unregister_snap_client, aka CID-9804501fa122. A remote attacker can perform a denial of service (DoS) attack.


Affected software

Linux kernel
Slackware Linux
Ubuntu
linux (Ubuntu package)
linux-raspi2 (Ubuntu package)
linux-kvm (Ubuntu package)
linux-aws (Ubuntu package)
linux-snapdragon (Ubuntu package)
linux-hwe (Ubuntu package)
linux-gcp (Ubuntu package)
linux-azure (Ubuntu package)
linux-oracle (Ubuntu package)
linux-gke-4.15 (Ubuntu package)
linux-aws-hwe (Ubuntu package)
linux-oracle-5.0 (Ubuntu package)
linux-gke-5.0 (Ubuntu package)
linux-aws-5.0 (Ubuntu package)

How to mitigate CVE-2019-19227

Update to version 5.1.

Linux kernel - update to 5.1
linux (Ubuntu package) - addressed in versions 4.4.0-173.203, 4.15.0-88.88
linux-raspi2 (Ubuntu package) - addressed in versions 4.4.0-1128.137, 4.15.0-1055.59
linux-kvm (Ubuntu package) - addressed in versions 4.4.0-1065.72, 4.15.0-1053.53
linux-aws (Ubuntu package) - addressed in versions 4.4.0-1101.112, 4.15.0-1060.62
linux-snapdragon (Ubuntu package) - addressed in versions 4.4.0-1132.140, 4.15.0-1072.79
linux-hwe (Ubuntu package) - update to 4.15.0-88.88~16.04.1
linux-gcp (Ubuntu package) - addressed in versions 4.15.0-1055.59, 5.0.0-1029.30~18.04.1
linux-azure (Ubuntu package) - update to 4.15.0-1071.76
linux-oracle (Ubuntu package) - addressed in versions 4.15.0-1033.36~16.04.1, 4.15.0-1033.36
linux-gke-4.15 (Ubuntu package) - update to 4.15.0-1052.55
linux-aws-hwe (Ubuntu package) - update to 4.15.0-1060.62~16.04.1
linux-oracle-5.0 (Ubuntu package) - update to 5.0.0-1010.15~18.04.1
linux-gke-5.0 (Ubuntu package) - update to 5.0.0-1029.30~18.04.1
linux-aws-5.0 (Ubuntu package) - update to 5.0.0-1024.27~18.04.1

External References

Related Security Bulletins