CVE-2016-7943
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain...
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
9.8
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
CVE-2016-7943- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-787
- Updated
- 2026-11-02
CVE List No score
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
CVE-2016-7943- Updated
- 2026-11-02
EUVDEUVD-2016-8792 No score
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
EUVD-2016-8792- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-84fh-jqg7-vh26
9.8
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain...
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
GHSA-84fh-jqg7-vh26- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-787
- Updated
- 2026-11-02
OSVALPINE-CVE-2016-7943
9.8
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
ALPINE-CVE-2016-7943- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVBELL-CVE-2016-7943
9.8
CVE-2016-7943 does not affect BellSoft software
- Record
BELL-CVE-2016-7943- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 5 moreShow less
OSV
9.8
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
CVE-2016-7943- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2016-7943
9.8
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
DEBIAN-CVE-2016-7943- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2016-7943
9.8
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
- Record
UBUNTU-CVE-2016-7943- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVMGASA-2018-0011 No score
Updated X11 client libraries packages fix security vulnerability
The XvQueryAdaptors and XvQueryEncodings functions in X.org libXv before 1.0.11 allow remote X servers to trigger out-of-bounds memory access operations via vectors involving length specifications in received data (CVE-2016-5407).
The XGetImage function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving image type and geometry, which triggers out-of-bounds read operations (CVE-2016-7942).
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations (CVE-2016-7943).
Integer overflow in X.org libXfixes before 5.0.3 on 32-bit platforms might allow remote X servers to gain privileges via a length value of INT_MAX, which triggers the client to stop reading data and get out of sync (CVE-2016-7944).
Multiple integer overflows in X.org libXi before 1.7.7 allow remote X servers to cause a denial of service (out-of-bounds memory access or infinite loop) via vectors involving length fields (CVE-2016-7945).
X.org libXi before 1.7.7 allows remote X servers to cause a denial of service (infinite loop) via vectors involving length fields (CVE-2016-7946).
Multiple integer overflows in X.org libXrandr before 1.5.1 allow remote X servers to trigger out-of-bounds write operations via a crafted response (CVE-2016-7947).
X.org libXrandr before 1.5.1 allows remote X servers to trigger out-of-bounds write operations by leveraging mishandling of reply data (CVE-2016-7948).
Multiple buffer overflows in the XvQueryAdaptors and XvQueryEncodings functions in X.org libXrender before 0.9.10 allow remote X servers to trigger out-of-bounds write operations via vectors involving length fields (CVE-2016-7949).
The XRenderQueryFilters function in X.org libXrender before 0.9.10 allows remote X servers to trigger out-of-bounds write operations via vectors involving filter name lengths (CVE-2016-7950).
Multiple integer overflows in X.org libXtst before 1.2.3 allow remote X servers to trigger out-of-bounds memory access operations by leveraging the lack of range checks (CVE-2016-7951).
X.org libXtst before 1.2.3 allows remote X servers to cause a denial of service (infinite loop) via a reply in the XRecordStartOfData, XRecordEndOfData, or XRecordClientDied category without a client sequence and with attached data (CVE-2016-7952).
Buffer underflow in X.org libXvMC before 1.0.10 allows remote X servers to have unspecified impact via an empty string (CVE-2016-7953).
- Record
MGASA-2018-0011- Updated
- 2026-11-02
OSVUSN-3758-1 No score
libx11 vulnerabilities
Tobias Stoeckmann discovered that libx11 incorrectly handled certain images. An attacker could possibly use this issue to access sensitive information (CVE-2016-7942)
Tobias Stoeckmann discovered that libx11 incorrectly handled certain inputs. An attacker could possibly use this issue to access sensitive information. (CVE-2016-7943)
It was discovered that libx11 incorrectly handled certain inputs. An attacker could possibly use this issue to cause a denial of service. (CVE-2018-14598, CVE-2018-14599, CVE-2018-14600)
- Record
USN-3758-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libx11Alpine:v3.2 |
before 1.6.3-r1 | 1.6.3-r1 |
libx11Alpine:v3.3 |
before 1.6.3-r3 | 1.6.3-r3 |
libx11Debian:12 |
before 2:1.6.4-1 | 2:1.6.4-1 |
libx11Debian:13 |
before 2:1.6.4-1 | 2:1.6.4-1 |
libx11Debian:14 |
before 2:1.6.4-1 | 2:1.6.4-1 |
libx11Debian:7 |
before 2:1.5.0-1+deb7u3, plus listed versions 2:1.5.0-12:1.5.0-1+deb7u12:1.5.0-1+deb7u2 |
2:1.5.0-1+deb7u3 |
libx11Mageia:5 |
before 1.6.5-1.mga5 | 1.6.5-1.mga5 |
libxvMageia:5 |
before 1.0.11-1.mga5 | 1.0.11-1.mga5 |
libxrenderMageia:5 |
before 0.9.10-1.mga5 | 0.9.10-1.mga5 |
libxtstMageia:5 |
before 1.2.3-1.mga5 | 1.2.3-1.mga5 |
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| Package | Affected | Fixed |
|---|---|---|
libxiMageia:5 |
before 1.7.7-1.mga5 | 1.7.7-1.mga5 |
libxrandrMageia:5 |
before 1.4.2-4.1.mga5 | 1.4.2-4.1.mga5 |
libxfixesMageia:5 |
before 5.0.3-1.mga5 | 5.0.3-1.mga5 |
libxvmcMageia:5 |
before 1.0.10-1.mga5 | 1.0.10-1.mga5 |
libx11Ubuntu:14.04:LTS |
before 2:1.6.2-1ubuntu2.1, plus listed versions 2:1.6.1-1ubuntu12:1.6.1-1ubuntu22:1.6.2-1ubuntu12:1.6.2-1ubuntu2 |
2:1.6.2-1ubuntu2.1 |
libx11Ubuntu:16.04:LTS |
before 2:1.6.3-1ubuntu2.1, plus listed versions 2:1.6.3-1ubuntu2 |
2:1.6.3-1ubuntu2.1 |
libx11Ubuntu:18.04:LTS |
before 2:1.6.4-3ubuntu0.1, plus listed versions 2:1.6.4-3 |
2:1.6.4-3ubuntu0.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2016-7943 is a critical vulnerability (CVSS 9.8) in X.org Libx11, published October 27, 2016. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 4.46%, the 91st percentile. Fixed in libx11 1.6.3-r1.
References
securitytracker.com/id/1036945
usn.ubuntu.com/3758-2
cgit.freedesktop.org/xorg/lib/libX11/commit?id=8c29f1607a31dac0911e45a0dd3d74173822b3c9
security.gentoo.org/glsa/201704-03
lists.x.org/archives/xorg-announce/2016-October/002720.html
openwall.com/lists/oss-security/2016/10/04/4
Show 20 moreShow less
openwall.com/lists/oss-security/2016/10/04/2
securityfocus.com/bid/93362
usn.ubuntu.com/3758-1
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GMCVDXMFPXR7QGMKDG22WPPJCXH2X3L7
nvd.nist.gov/vuln/detail/CVE-2016-7943
lists.fedoraproject.org/archives/list/[email protected]/message/GMCVDXMFPXR7QGMKDG22WPPJCXH2X3L7
github.com/advisories/GHSA-84fh-jqg7-vh26
security.alpinelinux.org/vuln/CVE-2016-7943
docs.bell-sw.com/security/cves/CVE-2016-7943
security-tracker.debian.org/tracker/CVE-2016-7943
advisories.mageia.org/MGASA-2018-0011.html
bugs.mageia.org/show_bug.cgi?id=19530
ubuntu.com/security/CVE-2016-7943
ubuntu.com/security/notices/USN-3758-2
ubuntu.com/security/notices/USN-3758-1
cve.org/CVERecord?id=CVE-2016-7943
ubuntu.com/security/CVE-2016-7942
ubuntu.com/security/CVE-2018-14598
ubuntu.com/security/CVE-2018-14599
ubuntu.com/security/CVE-2018-14600