How severe is CVE-2018-14040?

CVE-2018-14040 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2018-14040?

CVE-2018-14040 affects the following packages: org.webjars:bootstrap (Maven), org.webjars:bootstrap (Maven), bootstrap (npm), bootstrap (npm), bootstrap (NuGet), bootstrap (NuGet), bootstrap.sass (NuGet), twbs/bootstrap (Packagist), and 4 more. Ecosystems affected: Maven, npm, NuGet, Packagist, RubyGems.

How do I fix CVE-2018-14040?

Update org.webjars:bootstrap to 4.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-14040 is resolved across your whole dependency graph.

How do I detect CVE-2018-14040 in my Maven, npm, NuGet, Packagist, RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.webjars:bootstrap, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2018-14040 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2018-14040 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2018-14040, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2018-14040?

CVE-2018-14040 has an EPSS (Exploit Prediction Scoring System) score of 4.1%, placing it in the 91th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2018-14040?

CVE-2018-14040 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2018-14040 published, and has it been updated?

CVE-2018-14040 was published on July 13, 2018 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven📦 npm.NET NuGet🐘 Packagist💎 RubyGems

Not in CISA KEV

MEDIUM severity

CVE-2018-14040 — bootstrap

MEDIUMFix: twbs/bootstrap#26630

CVE-2018-14040 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in org.webjars:bootstrap. 2 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for org.webjars:bootstrap — see the affected versions and patch details below.

Bootstrap vulnerable to Cross-Site Scripting (XSS)

Also known asGHSA-3wqf-4x89-9g79

Published

Jul 13, 2018

Updated

Oct 20, 2026

Affected

12 pkgs

Patched

12 / 12

Exploits

2 known

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

4.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs91th percentile — riskier than 91% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

12 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

15Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

bootstrapnpm

8.1Mdownloads / week

Description

In Bootstrap starting in version 2.3.0 and prior to 3.4.0, as well as 4.x before 4.1.2, XSS is possible in the collapse data-parent attribute.

Affected Packages

12 total 12 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.webjars:bootstrap`	≥ 4.0.0&&< 4.1.2	4.1.2`org.webjars:bootstrap:4.1.2`
☕Maven	`org.webjars:bootstrap`	≥ 2.3.0&&< 3.4.0	3.4.0`org.webjars:bootstrap:3.4.0`
📦npm	`bootstrap`	≥ 4.0.0&&< 4.1.2	4.1.2`npm install bootstrap@4.1.2`
📦npm	`bootstrap`	≥ 2.3.0&&< 3.4.0	3.4.0`npm install bootstrap@3.4.0`
.NETNuGet	`bootstrap`	≥ 2.3.0&&< 3.4.0	3.4.0`dotnet add package bootstrap --version 3.4.0`
.NETNuGet	`bootstrap`	≥ 4.0.0&&< 4.1.2	4.1.2`dotnet add package bootstrap --version 4.1.2`

Affected Products

2 products · 12 configurations

debian linuxdebian

1 version

8.0

Application

bootstrapgetbootstrap

≥ 4.0.0 && < 4.1.2

1 version

4.0.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

In Bootstrap before 4.1.2, XSS is possible in the collapse data-parent a…

github.comNVDJul 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.webjars:bootstrap, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.webjars:bootstrap to 4.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-14040 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Red Hat Satellite 6.2 and newer versions don't use the bootstrap library, hence are not affected by this flaw. Red Hat CloudForms 4.6 and newer versions include the vulnerable component, but there is no risk of exploitation, since there is no possible vector to access the vulnerability. Older Red Hat CloudForms…

Product	Fixed in	Advisory
Red Hat Enterprise Linux 7	`ipa-0:4.6.8-5.el7`	RHSA-2020:3936
Red Hat Enterprise Linux 8	`idm:client-8030020200923172426.05ac3f11`	RHSA-2020:4670
Red Hat Enterprise Linux 8	`pki-core:10.6-8030020200911215836.5ff1562f`	RHSA-2020:4847
Red Hat JBoss Enterprise Application Platform 7.4.9	`org.jboss.hal/hal-console:3.3.16.Final-redhat-00001`	RHSA-2023:0556
Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 8	`eap7-hal-console-0:3.3.16-1.Final_redhat_00001.1.el8eap`	RHSA-2023:0553
Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 9	`eap7-hal-console-0:3.3.16-1.Final_redhat_00001.1.el9eap`	RHSA-2023:0554
Red Hat JBoss Enterprise Application Platform 7.4 on RHEL 7	`eap7-hal-console-0:3.3.16-1.Final_redhat_00001.1.el7eap`	RHSA-2023:0552
Red Hat Single Sign-On 7	`keycloak-theme`	RHSA-2023:1049

Frequently Asked Questions

In Bootstrap starting in version 2.3.0 and prior to 3.4.0, as well as 4.x before 4.1.2, XSS is possible in the collapse data-parent attribute.

O3 Security · Impact-Aware SCA

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