CVE-2018-1999024 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in mathjax. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for mathjax — see the affected versions and patch details below.
Macro in MathJax running untrusted Javascript within a web browser
EPSS Exploitation Probability
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
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.
mathjaxnpmDescription
MathJax version prior to version 2.7.4 contains a Cross Site Scripting (XSS) vulnerability in the \unicode{} macro that can result in Potentially untrusted Javascript running within a web browser. This attack appear to be exploitable via The victim must view a page where untrusted content is processed using Mathjax. This vulnerability appears to have been fixed in 2.7.4 and later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | mathjax | all versions | 2.7.4npm install mathjax@2.7.4 |
Affected Products
mathjaxmathjaxResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mathjax, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mathjax to 2.7.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1999024 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.
Frequently Asked Questions
Is CVE-2018-1999024 in your dependencies?
Find it across npm, including transitive dependencies.