CVE-2026-49255 is a high-severity (CVSS 8.8) OS Command Injection vulnerability in electerm. A fix is available for electerm — see the affected versions and patch details below.
electerm: Command Injection in File System Operations (rmrf, mv, cp)
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-2026-49255.
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-2026-49255 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 377,166 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
electerm is an open-sourced terminal/ssh/sftp/telnet/serialport/RDP/VNC/Spice/ftp client. Prior to 3.11.11, electerm constructs operating system commands in src/app/lib/fs.js by interpolating untrusted file paths into the rmrf(), mv(), and cp() functions. A malicious SSH or SFTP server can provide a filename containing quote characters and shell metacharacters, and a victim can cause that filename to reach the affected operation during remote-to-local transfer, conflict renaming, copying, moving, or removal. The generated rm -rf, mv, cp -r, PowerShell Remove-Item, Move-Item, or Copy-Item command can then interpret the filename as shell syntax. This allows arbitrary command execution with the electerm desktop user's privileges on POSIX and Windows systems, enabling data exfiltration, file modification, malware installation, or denial of service. This issue is fixed in version 3.11.11.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electerm | all versions | 3.11.11npm install electerm@3.11.11 |
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 3.11.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-49255 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-2026-49255 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-49255. 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-2026-49255 in your dependencies?
O3 Security finds CVE-2026-49255 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.