#VU15929 Null pointer dereference in libxkbcommon - CVE-2018-15863

Vulnerability identifier: #VU15929

Vulnerability risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-15863

CWE-ID: CWE-476

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
libxkbcommon
Universal components / Libraries / Libraries used by multiple products

Vendor: xkbcommon

Description

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

The vulnerability exists due to NULL pointer usage condition by the ResolveStateAndPredicate function, as defined in the xkbcomp/compat.c source code file. A local attacker can submit a specially crafted keymap file that submits malicious input to an affected system with a no-op modmaskexpression, trigger NULL pointer dereference and cause the application to crash.

Mitigation
Update to version 0.8.2.

Vulnerable software versions

libxkbcommon: 0.2 - 0.8.1

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External links
https://github.com/xkbcommon/libxkbcommon/commit/96df3106d49438e442510c59acad306e94f3db4d

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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.