CVE-2026-43943 is a high-severity (CVSS 7.8) OS Command Injection vulnerability in electerm. A fix is available for electerm — see the affected versions and patch details below.
electerm: RCE via malicious SSH server filename in openFileWithEditor
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-43943.
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-2026-43943 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 378,156 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.
electermnpmDescription
Impact
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.
<img width="1792" height="817" alt="1" src="https://github.com/user-attachments/assets/ddf78890-e95d-4fe7-981e-f86887677e8b" /> <img width="1648" height="941" alt="2" src="https://github.com/user-attachments/assets/cca2295b-2053-4d99-a464-be51eac2f5be" />Patches
Fixed in version >= 3.7.9
Workarounds
Until a patch is available, it is strongly recommended to:
- Refrain from using the open with system editor or "Edit with custom editor" feature when connected to untrusted or unfamiliar SSH servers.
- Consider using the built-in editor for viewing files, as this path may not be vulnerable to the same injection.
- If the feature must be used, ensure connections are exclusively established with trusted servers and perform rigorous filename validation before editing.
Resources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electerm | all versions | 3.7.9npm install electerm@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-43943 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2026-43943 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.