Multiple vulnerabilities in X libXfont

Published: 2017-10-11 | Updated: 2020-08-08

Risk	Low
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2017-13720 CVE-2017-13722
CWE-ID	CWE-125
Exploitation vector	Local
Public exploit	N/A
Vulnerable software Subscribe	libXfont Universal components / Libraries / Libraries used by multiple products
Vendor	X.org

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Out-of-bounds read

EUVDB-ID: #VU38075

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 - Out-of-bounds read

Exploit availability: No

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

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

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.

2) Out-of-bounds read

EUVDB-ID: #VU38076