#VU11524 Out-of-bounds read in Linux kernel - CVE-2018-1093

Vulnerability identifier: #VU11524

Vulnerability risk: Low

CVSSv4.0: 4.3 [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/E:U/U:Clear]

CVE-ID: CVE-2018-1093

CWE-ID: CWE-125

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description
The vulnerability allows a local attacker to cause DoS condition on the target system.

The weakness exists due to improper validation of bitmap block numbers by the balloc.c and ialloc.c source codes. A local attacker can mount a customized ext4 image, trigger out-of-bounds read in the ext4/balloc.c:ext4_valid_block_bitmap() function ans cause the service to crash.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 4.0.1 - 4.0.6, 4.1 - 4.15.15, 4.2 - 4.2.6, 4.3 - 4.3.6, 4.4.0 - 4.4.111, 4.5 - 4.5.4, 4.6 rc1 - 4.6.3, 4.7 - 4.7.9, 4.8 - 4.8.12, 4.9 - 4.9.76

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External links
https://bugzilla.kernel.org/show_bug.cgi?id=199181

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.