CVE-2017-12186
CRITICALEPSS 91th pctlDescription
xorg-x11-server before 1.19.5 was missing length validation in X-Resource extension allowing malicious X client to cause X server to crash or possibly execute arbitrary code.
How to fix
This Ubuntu release reached end-of-life on 2019-04-02.
This Ubuntu release reached end-of-life on 2019-04-02.
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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
High risk: more likely to be exploited than 91% of all known CVEs.
References
Related Vulnerabilities
Other CWE-391 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-52316 | Critical | 9.8 | 6.2% | - | Fix |
| CVE-2017-12179 | Critical | 9.8 | 4.4% | - | Fix |
| CVE-2017-12177 | Critical | 9.8 | 4.4% | - | Fix |
| CVE-2017-12183 | Critical | 9.8 | 4.2% | - | Fix |
| CVE-2017-12182 | Critical | 9.8 | 4.2% | - | Fix |
| CVE-2017-12181 | Critical | 9.8 | 4.2% | - | Fix |
Common questions
How do I fix CVE-2017-12186?
Published advisories record a fix for 7 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2017-12186 being actively exploited?
Not that we know of. CVE-2017-12186 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 4.3% is the estimated probability that it will be exploited in the next 30 days. That is higher than 91% of all scored CVEs.
How severe is CVE-2017-12186?
CVE-2017-12186 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2017-12186 affect?
Published advisories record a fix for xorg-server (Debian), xorg-server (Ubuntu), xorg-server-hwe-16.04 (Ubuntu), xorg-server-lts-xenial (Ubuntu), and 3 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.