#VU15927 Null pointer dereference in libxkbcommon - CVE-2018-15861

Vulnerability identifier: #VU15927

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-2018-15861

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 ExprResolveLhs function, as defined in the xkbcomp/expr.c source code file. A local attacker can submit a specially crafted keymap file that submits malicious input, trigger an xkb_intern_atom failure and cause the application to crash.

Mitigation
Update to version 0.8.2.

Vulnerable software versions

libxkbcommon: 0.2 - 0.8.1

---

External links
https://github.com/xkbcommon/libxkbcommon/commit/38e1766bc6e20108948aec8a0b222a4bad0254e9

---

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.