CVE-2026-43943 is a high-severity (CVSS 7.8) remote code execution vulnerability in electerm. O3 Security confirms whether CVE-2026-43943 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
electerm: RCE via malicious SSH server filename in openFileWithEditor
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
electermnpmDescription
electerm is an open-sourced terminal/ssh/sftp/telnet/serialport/RDP/VNC/Spice/ftp client. Prior to version 3.7.9, a code execution (RCE) vulnerability exists in electerm's SFTP open with system editor or "Edit with custom editor" feature. When a user opts to edit a file using open with system editor or open with a custom editor, the filename is passed directly into a command line without sanitization. A malicious actor controlling the SSH server or user OS can exploit this by crafting a filename containing shell metacharacters. If a victim subsequently attempts to edit this file, the injected commands are executed on their machine with the user's privileges. This could allow the attacker to run arbitrary code, install malware, or move laterally within the network. This issue has been patched in version 3.7.9.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electerm | all versions | 3.7.9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for electerm. 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 electerm to 3.7.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43943 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-2026-43943 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-2026-43943. 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-2026-43943 in your dependencies?
O3 detects CVE-2026-43943 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.