An issue was discovered in libX11 through 1.6.5.
An issue was discovered in libX11 through 1.6.5. The function XListExtensions in ListExt.c is vulnerable to an off-by-one error caused by malicious server responses, leading to DoS or possibly unspecified other impact.
- Published
- Aug 24, 2018
- Updated
- Jun 16, 2026
- EPSS
- 4.8% · 92th percentile
- CWE
- CWE-193
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Report tools
Action score
40
Plan
Add it to your regular patch cycle.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 4.8%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| x.org | libx11 | cpe:2.3:a:x.org:libx11 |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux workstation | cpe:2.3:o:redhat:enterprise_linux_workstation |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux12.04
- canonical ubuntu linux14.04
- canonical ubuntu linux16.04
- canonical ubuntu linux18.04
- debian debian linux8.0
- fedoraproject fedora28
- redhat enterprise linux desktop7.0
- redhat enterprise linux server7.0
- redhat enterprise linux workstation7.0
- x.org libx11up to 1.6.5 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | libx11 | before 1.6.6-r0 | 1.6.6-r0 |
| Debian:12 | libx11 | before 2:1.6.6-1 | 2:1.6.6-1 |
| Debian:8 | libx11 | before 2:1.6.2-3+deb8u2 | 2:1.6.2-3+deb8u2 |
| openSUSE:Tumbleweed | libX11 | before 1.7.2-1.2 | 1.7.2-1.2 |
| Red Hat:enterprise_linux:7::client | gdm | before 1:3.28.2-16.el7 | 1:3.28.2-16.el7 |
| Red Hat:enterprise_linux:7::client | gdm-debuginfo | before 1:3.28.2-16.el7 | 1:3.28.2-16.el7 |
| Red Hat:enterprise_linux:7::client | gdm-devel | before 1:3.28.2-16.el7 | 1:3.28.2-16.el7 |
| Red Hat:enterprise_linux:7::client | gdm-pam-extensions-devel | before 1:3.28.2-16.el7 | 1:3.28.2-16.el7 |
| Red Hat:enterprise_linux:7::client | libX11 | before 0:1.6.7-2.el7 | 0:1.6.7-2.el7 |
| Red Hat:enterprise_linux:7::client | libX11-common | before 0:1.6.7-2.el7 | 0:1.6.7-2.el7 |
| Red Hat:enterprise_linux:7::client | libX11-debuginfo | before 0:1.6.7-2.el7 | 0:1.6.7-2.el7 |
| Red Hat:enterprise_linux:7::client | libX11-devel | before 0:1.6.7-2.el7 | 0:1.6.7-2.el7 |
| Red Hat:enterprise_linux:7::client | libxkbcommon | before 0:0.7.1-3.el7 | 0:0.7.1-3.el7 |
| Red Hat:enterprise_linux:7::client | libxkbcommon-debuginfo | before 0:0.7.1-3.el7 | 0:0.7.1-3.el7 |
| Red Hat:enterprise_linux:7::client | libxkbcommon-devel | before 0:0.7.1-3.el7 | 0:0.7.1-3.el7 |
| Red Hat:enterprise_linux:7::client | libxkbcommon-x11 | before 0:0.7.1-3.el7 | 0:0.7.1-3.el7 |
| Red Hat:enterprise_linux:7::client | libxkbcommon-x11-devel | before 0:0.7.1-3.el7 | 0:0.7.1-3.el7 |
| Red Hat:enterprise_linux:7::client | xorg-x11-drv-ati | before 0:19.0.1-2.el7 | 0:19.0.1-2.el7 |
| Red Hat:enterprise_linux:7::client | xorg-x11-drv-ati-debuginfo | before 0:19.0.1-2.el7 | 0:19.0.1-2.el7 |
| Red Hat:enterprise_linux:7::client | xorg-x11-drv-vesa | before 0:2.4.0-3.el7 | 0:2.4.0-3.el7 |
| Red Hat:enterprise_linux:7::client | xorg-x11-drv-vesa-debuginfo | before 0:2.4.0-3.el7 | 0:2.4.0-3.el7 |
| Red Hat:enterprise_linux:7::client | xorg-x11-drv-wacom | before 0:0.36.1-3.el7 | 0:0.36.1-3.el7 |
| Red Hat:enterprise_linux:7::client | xorg-x11-drv-wacom-debuginfo | before 0:0.36.1-3.el7 | 0:0.36.1-3.el7 |
| Red Hat:enterprise_linux:7::client | xorg-x11-drv-wacom-devel | before 0:0.36.1-3.el7 | 0:0.36.1-3.el7 |
+18
Same product
x.org: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-31535LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code.42Plan
- CVE-2018-14600An issue was discovered in libX11 through 1.6.5.42Plan
- CVE-2016-7943The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, wh40Plan
- CVE-2016-7942The XGetImage function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving image type and geo40Plan
- CVE-2007-1667Multiple integer overflows in (1) the XGetPixel function in ImUtil.c in X.Org libx11 before 1.0.3, and (2) XInitImage function in xwd.c for 38Monitor
- CVE-2023-43787Libx11: integer overflow in xcreateimage() leading to a heap overflow31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:libx11 | 1.6.6-r0 · Alpine:v3.10 | Package registry (OSV) |
| debian:libx11 | 2:1.6.6-1 · Debian:12 | Package registry (OSV) |
| opensuse:libX11 | 1.7.2-1.2 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:gdm | 1:3.28.2-16.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:gdm-debuginfo | 1:3.28.2-16.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libX11 | 0:1.6.7-2.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libX11-common | 0:1.6.7-2.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libX11-debuginfo | 0:1.6.7-2.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libX11-devel | 0:1.6.7-2.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libxkbcommon | 0:0.7.1-3.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libxkbcommon-debuginfo | 0:0.7.1-3.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libxkbcommon-x11 | 0:0.7.1-3.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:xorg-x11-drv-ati | 0:19.0.1-2.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:xorg-x11-drv-ati-debuginfo | 0:19.0.1-2.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:xorg-x11-drv-vesa | 0:2.4.0-3.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:libX11 | 1.6.5-3.3.1 · SUSE:Linux Enterprise Module for Basesystem 15 | Package registry (OSV) |
| suse:libxcb | 1.10-4.3.1 · SUSE:Linux Enterprise Desktop 12 SP3 | Package registry (OSV) |
| suse:xorg-x11-libX11 | 7.4-5.11.72.9.1 · SUSE:Linux Enterprise Software Development Kit 11 SP4 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-193 · Off-by-one ErrorCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.openwall.com/lists/oss-security/2018/08/21/6
- www.securityfocus.com/bid/105177
- www.securitytracker.com/id/1041543
- access.redhat.com/errata/RHSA-2019:2079
- bugzilla.suse.com/show_bug.cgi?id=1102062
- cgit.freedesktop.org/xorg/lib/libX11/commit/?id=b469da1430cdcee06e31c6251b83aede072a1ff0
- lists.debian.org/debian-lts-announce/2018/08/msg00030.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YGARUV66TS5OOSLR5A76BUB7SDV6GO4F/
- lists.x.org/archives/xorg-announce/2018-August/002916.html
- security.gentoo.org/glsa/201811-01
- usn.ubuntu.com/3758-1/
- usn.ubuntu.com/3758-2/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.