Summary
Electerm runWidget has a path traversal that leads to arbitrary code execution
Fixed in version >= 3.7.16
Workarounds
Until a patch is released:
- Do not install or run untrusted plugins.
- Avoid loading arbitrary web content inside electerm’s embedded webview (for example, disable any features that fetch and display remote HTML).
- Run electerm in a sandboxed environment (e.g., with
bubblewrapon Linux, AppArmor/SELinux profiles, or Windows sandboxed app execution) to limit the impact of any code execution.
Resources
- electerm GitHub Repository
- electerm Security Policy
- Vulnerability details originally reported by external researcher (PoC confirmed on v3.7.9, Win10).
Impact
The runWidget function in src/app/widgets/load-widget.js constructs a file path by directly concatenating user‑supplied widget identifiers without any sanitisation:
const file = `widget-${widgetId}.js`
const widget = require(path.join(__dirname, file))
Because runWidget is exposed to the renderer process via an asynchronous IPC handler with no input validation, an attacker who achieves JavaScript execution inside the renderer (for example, through a malicious plugin or a cross‑site scripting flaw in the built‑in webview) can abuse a path traversal (../) to load and execute an arbitrary JavaScript file anywhere on the victim’s filesystem. This gives the attacker local code execution with the full privileges of the electerm process, leading to complete system compromise.
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-43940 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.7.16); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-43940? CVE-2026-43940 is a critical-severity path traversal vulnerability in electerm (npm), affecting versions < 3.7.16. It is fixed in 3.7.16. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-43940? CVE-2026-43940 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of electerm are affected by CVE-2026-43940? electerm (npm) versions < 3.7.16 is affected.
- Is there a fix for CVE-2026-43940? Yes. CVE-2026-43940 is fixed in 3.7.16. Upgrade to this version or later.
- Is CVE-2026-43940 exploitable, and should I be worried? Whether CVE-2026-43940 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-43940 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-43940? Upgrade
electermto 3.7.16 or later.