Vulnerability identifier: #VU38075

Vulnerability risk: Low

CVSSv3.1: 6.2 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-13720

CWE-ID: CWE-125

Exploitation vector: Local

Exploit availability: No

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

Vendor: X.org

Description

The vulnerability allows a local authenticated user to #BASIC_IMPACT#.

In the PatternMatch function in fontfile/fontdir.c in libXfont through 1.5.2 and 2.x before 2.0.2, an attacker with access to an X connection can cause a buffer over-read during pattern matching of fonts, leading to information disclosure or a crash (denial of service). This occurs because '' characters are incorrectly skipped in situations involving ? characters.

Mitigation
Install update from vendor's website.

Vulnerable software versions

libXfont: 2.0.0 - 2.0.1

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External links
http://www.debian.org/security/2017/dsa-3995
http://bugzilla.redhat.com/show_bug.cgi?id=1500690
http://bugzilla.suse.com/show_bug.cgi?id=1054285
http://cgit.freedesktop.org/xorg/lib/libXfont/commit/?id=d1e670a4a8704b8708e493ab6155589bcd570608
http://security.gentoo.org/glsa/201711-08
http://www.x.org/releases/individual/lib/libXfont2-2.0.2.tar.bz2

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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.