CVE-2018-1092: Null Pointer Dereference
Last updated 4 July 2026
Other sources
The ext4iget function in fs/ext4/inode.c in the Linux kernel through 4.15.15 mishandles the case of a root directory with a zero ilinkscount, which allows attackers to cause a denial of service (ext4processfreeddata NULL pointer dereference and OOPS) via a crafted ext4 image.
— Launchpad
The Linux kernel is vulnerable to a NULL pointer dereference in the ext4/mballoc.c:ext4processfreeddata() function. An attacker could trick a legitimate user or a privileged attacker could exploit this by mounting a crafted ext4 image to cause a kernel panic.
References:
https://bugzilla.kernel.org/showbug.cgi?id=199179 (reproducer #1)
https://bugzilla.kernel.org/showbug.cgi?id=199275 (reproducer #2)
http://seclists.org/oss-sec/2018/q1/284
An upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8e4b5eae5decd
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.262-1Fixed in 6.1.176-1Fixed in 6.1.180-1Fixed in 6.12.94-1Fixed in 6.12.101-1Fixed in 7.1.8-1Fixed in 7.1.8-2 - Upgrade
Upgrade
Linux kernel (ext4)to a version that resolves this vulnerability.Fixed in 4.15.15
Event History
Frequently Asked Questions
What is the severity of CVE-2018-1092?
CVE-2018-1092 has a medium severity level due to its potential to cause a denial of service.
How does CVE-2018-1092 affect the Linux kernel?
CVE-2018-1092 affects the ext4_iget function in the Linux kernel, which mishandles a root directory with a zero i_links_count.
What versions of the Linux kernel are affected by CVE-2018-1092?
CVE-2018-1092 affects the Linux kernel versions up to and including 4.15.15.
How can I fix CVE-2018-1092?
To mitigate CVE-2018-1092, upgrade to a patched version of the Linux kernel, such as 5.10.223-1 or later.
What type of attack can exploit CVE-2018-1092?
Attackers can exploit CVE-2018-1092 to cause a denial of service through a NULL pointer dereference.