An issue was discovered in XListExtensions in ListExt.c in libX11 through 1.6.5. A malicious server can send a reply in which the first string overflows, causing a variable to be set to NULL that will be freed later on, leading to DoS (segmentation fault).
Conclusion & alert: CVE-2018-14598 is rated Moderate Risk (63.5/100): CVSS High severity, with high exploitation likelihood (EPSS 4.76%, 91th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +1.73% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
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 | 2026-06-15 | 3.03% | 4.76% | +1.73% |
| 2 | 2026-04-12 | 1.10% | 3.03% | +1.93% |
| 3 | 2026-02-27 | — | 1.10% | — |
Full EPSS history (24 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.0 | HIGH |
|
3.9 | 3.6 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
high | CVE-2018-14598: 1 source package rows (libx11); 10 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 0. | https://security.alpinelinux.org/vuln/CVE-2018-14598 |
debian
|
low | CVE-2018-14598 low priority: Debian including 1 source packages (libx11), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2018-14598 |
gentoo
|
normal | CVE-2018-14598: 1 GLSA(s) (201811-01), 1 atom(s) (x11-libs/libX11); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-14598 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2018-14598 |
suse
|
medium | CVE-2018-14598 severity moderate: SUSE including 398 source package names (0.38.1:libX11-6-1.6.5-3.3.1, 0.38.1:libX11-data-1.6.5-3.3.1, …), 1136 product×package rows across 204 product lines (Container bci/openjdk, Container bci/openjdk-devel, … (204 product lines)): Fixed 905, Known Affected 231. | https://www.suse.com/security/cve/CVE-2018-14598/ |
ubuntu
|
medium | CVE-2018-14598 medium priority: Ubuntu including 1 source packages (libx11), 4 status rows across 4 suites (bionic, trusty, upstream, xenial): released 4. | https://ubuntu.com/security/CVE-2018-14598 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| x.org | libx11 | <= 1.6.5 | cpe:2.3:a:x.org:libx11:*:*:*:*:*:*:*:* |
| canonical | ubuntu_linux | 12.04 | cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:esm:*:*:* |
| canonical | ubuntu_linux | 14.04 | cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* |
| canonical | ubuntu_linux | 16.04 | cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* |
| canonical | ubuntu_linux | 18.04 | cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* |
| debian | debian_linux | 8.0 | cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* |
| fedoraproject | fedora | 28 | cpe:2.3:o:fedoraproject:fedora:28:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| http://www.openwall.com/lists/oss-security/2018/08/21/6 | Mailing List Third Party Advisory |
| http://www.securityfocus.com/bid/105177 | Third Party Advisory VDB Entry |
| http://www.securitytracker.com/id/1041543 | Third Party Advisory VDB Entry |
| https://access.redhat.com/errata/RHSA-2019:2079 | |
| https://bugzilla.suse.com/show_bug.cgi?id=1102073 | Issue Tracking Patch Third Party Advisory |
| https://cgit.freedesktop.org/xorg/lib/libX11/commit/?id=e83722768fd5c467ef61fa159e8c6278770b45c2 | Patch Third Party Advisory |
| https://lists.debian.org/debian-lts-announce/2018/08/msg00030.html | Third Party Advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YGARUV66TS5OOSLR5A76BUB7SDV6GO4F/ | |
| https://lists.x.org/archives/xorg-announce/2018-August/002916.html | Third Party Advisory |
| https://security.gentoo.org/glsa/201811-01 | Third Party Advisory |
| https://usn.ubuntu.com/3758-1/ | Third Party Advisory |
| https://usn.ubuntu.com/3758-2/ | Third Party Advisory |