CVE-2021-43862 is a medium-severity (CVSS 5.4) CWE-80 vulnerability in jquery.terminal. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2021-43862 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
jquery.terminal self XSS on user input
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2021-43862 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 365,017 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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.
jquery.terminalnpmDescription
jQuery Terminal Emulator is a plugin for creating command line interpreters in your applications. Versions prior to 2.31.1 contain a low impact and limited cross-site scripting (XSS) vulnerability. The code for XSS payload is always visible, but an attacker can use other techniques to hide the code the victim sees. If the application uses the execHash option and executes code from URL, the attacker can use this URL to execute their code. The scope is limited because the javascript attribute used is added to span tag, so no automatic execution like with onerror on images is possible. This issue is fixed in version 2.31.1. As a workaround, the user can use formatting that wrap whole user input and its no op. The code for this workaround is available in the GitHub Security Advisory. The fix will only work when user of the library is not using different formatters (e.g. to highlight code in different way).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jquery.terminal | all versions | 2.31.1 |
Research 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 jquery.terminal. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update jquery.terminal to 2.31.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-43862 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-43862 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2021-43862. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-43862 in your dependencies?
O3 detects CVE-2021-43862 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.