CVE-2026-43940: Electerm Path Traversal Vulnerability

CRITICAL
Advisory Identifier: GHSA-f77v-9vpc-6pjm
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CVSS 9.8
CWE-829 CWE-22
Published
Advisory Summary

CVE-2026-43940 is a CRITICAL (CVSS 9.8) path traversal vulnerability (CWE-829: Inclusion of Functionality from Untrusted Control Sphere) affecting Electerm libraries in the npm ecosystem. The issue involves electerm runwidget has a path traversal that leads to arbitrary code execution. Remediation is available by upgrading affected packages to version 3.7.16.

CVE-2026-43940 at a Glance

CVE Identifier CVE-2026-43940
GHSA Identifier GHSA-f77v-9vpc-6pjm
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-829: Inclusion of Functionality from Untrusted Control Sphere
Affected Product Electerm
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-43940

To remediate this vulnerability, upgrade all affected Electerm dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

electerm fixed: 3.7.16 
npm install electerm@3.7.16
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls electerm

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-43940, inspect your project dependencies using npm:

npm ls electerm

Analyze the terminal output to locate any version of Electerm in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.7.16), your application is affected.

Note: The npm ls electerm command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-829: Inclusion of Functionality from Untrusted Control Sphere, where the product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere. In Electerm, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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: ```javascript 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. ### Patches 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 `bubblewrap` on Linux, AppArmor/SELinux profiles, or Windows sandboxed app execution) to limit the impact of any code execution. ### Resources - [electerm GitHub Repository](https://github.com/electerm/electerm) - [electerm Security Policy](https://github.com/electerm/electerm/security) - Vulnerability details originally reported by external researcher (PoC confirmed on v3.7.9, Win10).

CVE-2026-43940 Affected Electerm Versions

1 component(s)
Fixed Versions:
3.7.16
Product / Package Ecosystem Affected Versions Fixed Version
electerm
npm/electerm
npm
< 3.7.16
3.7.16

References

Electerm Source Repository REPOSITORY
https://github.com/electerm/electerm
GitHub Advisory / Wiki ADVISORY
https://github.com/electerm/electerm/security/advisories/GHSA-f77v-9vpc-6pjm
NVD — CVE-2026-43940 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-43940
Electerm Release RELEASE
https://github.com/electerm/electerm/releases/tag/v3.7.16

Frequently Asked Questions

What is CVE-2026-43940?
CVE-2026-43940 is a security vulnerability in Electerm involving Electerm runWidget has a path traversal that leads to arbitrary code execution under CWE-829: Inclusion of Functionality from Untrusted Control Sphere.
Which Electerm versions are affected?
Affected versions include releases prior to 3.7.16 across affected packages: electerm.
What version fixes CVE-2026-43940?
Upgrading to 3.7.16 (or the latest patched release for your respective branch) resolves the vulnerability.
Is electerm affected?
Yes, electerm is affected in releases prior to 3.7.16. Upgrade your dependency to 3.7.16 or later.
What is the CVSS score of CVE-2026-43940?
CVE-2026-43940 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-43940?
CVE-2026-43940 is classified under CWE-829: Inclusion of Functionality from Untrusted Control Sphere (The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.).
How can I check npm dependencies for CVE-2026-43940?
Run the dependency tree command: 'npm ls electerm'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-f77v-9vpc-6pjm",
  "modified" : "2026-05-08T18:34:20Z",
  "published" : "2026-05-08T18:34:20Z",
  "aliases" : [ "CVE-2026-43940" ],
  "summary" : "Electerm runWidget has a path traversal that leads to arbitrary code execution",
  "details" : "### Impact\nThe `runWidget` function in `src/app/widgets/load-widget.js` constructs a file path by directly concatenating user‑supplied widget identifiers without any sanitisation:\n\n```javascript\nconst file = `widget-${widgetId}.js`\nconst widget = require(path.join(__dirname, file))\n```\n\nBecause `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.\n\n### Patches\n\nFixed in version >= 3.7.16\n\n### Workarounds\nUntil a patch is released:\n- Do not install or run untrusted plugins.\n- Avoid loading arbitrary web content inside electerm’s embedded webview (for example, disable any features that fetch and display remote HTML).\n- Run electerm in a sandboxed environment (e.g., with `bubblewrap` on Linux, AppArmor/SELinux profiles, or Windows sandboxed app execution) to limit the impact of any code execution.\n\n### Resources\n- [electerm GitHub Repository](https://github.com/electerm/electerm)\n- [electerm Security Policy](https://github.com/electerm/electerm/security)\n- Vulnerability details originally reported by external researcher (PoC confirmed on v3.7.9, Win10).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "electerm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.7.16"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/electerm/electerm/security/advisories/GHSA-f77v-9vpc-6pjm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-43940"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/electerm/electerm"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/electerm/electerm/releases/tag/v3.7.16"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-829" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-08T18:34:20Z",
    "nvd_published_at" : "2026-05-08T04:16:23Z"
  }
}