CVE-2017-13720

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 '\0' characters are incorrectly skipped in situations involving ? characters.

Published: 2017-10-11 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-13720 is rated Low Risk (38.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.10%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2017-13720

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-07-12 0.04% 0.10% +0.06%
2 2025-03-30 0.10% 0.04% -0.06%
3 2025-03-29 — 0.10% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-13720

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.0 HIGH
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.2 [email protected]
3.6 2.0 LOW
AV:L/AC:L/Au:N/C:P/I:N/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 4.9 [email protected]

Weakness enumeration for CVE-2017-13720

OS Trackers for CVE-2017-13720

vendor priority summary link
debian not yet assigned CVE-2017-13720 not yet assigned priority: Debian including 1 source packages (libxfont), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-13720
gentoo normal CVE-2017-13720: 1 GLSA(s) (201711-08), 2 atom(s) (x11-libs/libXfont, x11-libs/libXfont2); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2017-13720
redhat low — https://access.redhat.com/security/cve/CVE-2017-13720
suse medium CVE-2017-13720 severity moderate: SUSE including 252 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 375 product×package rows across 62 product lines (SUSE CaaS Platform 4.0, SUSE CaaS Platform 4.5, … (62 product lines)): Known Affected 231, Known Not Affected 93, Fixed 51. https://www.suse.com/security/cve/CVE-2017-13720/
ubuntu low CVE-2017-13720 low priority: Ubuntu including 3 source packages (libxfont, libxfont1, libxfont2), 12 status rows across 4 suites (trusty, upstream, xenial, zesty): released 5, DNE 4, needs-triage 3. https://ubuntu.com/security/CVE-2017-13720

Affected software / configurations for CVE-2017-13720

Vendor Product Version Raw CPE
x.org libxfont <= 1.5.2 cpe:2.3:a:x.org:libxfont:*:*:*:*:*:*:*:*
x.org libxfont 2.0.0 cpe:2.3:a:x.org:libxfont:2.0.0:*:*:*:*:*:*:*
x.org libxfont 2.0.1 cpe:2.3:a:x.org:libxfont:2.0.1:*:*:*:*:*:*:*

References for CVE-2017-13720

cvelogic Threat Intelligence