CVE-2018-1093: Medium severity Linux Linux kernel vulnerability
Last updated 4 July 2026
Other sources
The ext4validblockbitmap function in fs/ext4/balloc.c in the Linux kernel through 4.15.15 allows attackers to cause a denial of service (out-of-bounds read and system crash) via a crafted ext4 image because balloc.c and ialloc.c do not validate bitmap block numbers.
— Launchpad
The Linux kernel is vulnerable to an out-of-bounds read in ext4/balloc.c:ext4validblockbitmap() function. An attacker could trick a legitimate user or a privileged attacker could exploit this by mounting a crafted ext4 image to cause a crash.
References:
https://bugzilla.kernel.org/showbug.cgi?id=199181
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=7dac4a1726a9c
— 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 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1 - Upgrade
Upgrade
Linux kernelto a version that resolves this vulnerability.Fixed in 4.15.15 - Compensating control
Mitigate by avoiding mounting untrusted/crafted ext4 images; restrict who can supply or mount ext4 filesystem images to reduce exposure to the ext4_valid_block_bitmap() out-of-bounds read crash condition.
Event History
Frequently Asked Questions
What is the vulnerability ID?
The vulnerability ID is CVE-2018-1093.
What is the severity of CVE-2018-1093?
The severity of CVE-2018-1093 is low.
What is the affected software?
The affected software includes the Linux kernel versions 4.15.15 and below.
How can attackers exploit CVE-2018-1093?
Attackers can exploit CVE-2018-1093 by crafting a malicious ext4 image that causes an out-of-bounds read and system crash.
Are there any references for more information about CVE-2018-1093?
Yes, you can find more information about CVE-2018-1093 at the following references: - http://openwall.com/lists/oss-security/2018/03/29/1 - https://bugzilla.kernel.org/show_bug.cgi?id=199181 - https://bugzilla.redhat.com/show_bug.cgi?id=1560782