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CVE-2026-43941VulnerabilityPublished

Electerm has an unvalidated shell.openExternal that allows arbitrary protocol execution via terminal link click

Affects electermSource GCVE Database

0
Authoritative record:CVE-2026-43941· Critical 9.6

Not known to be exploited · CVSS 9.6 Critical.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score
9.6Critical
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
npmelectermAffected
  • <=3.8.15
Fixed in–

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Description

### Impact Electerm's terminal hyperlink handler passes any URL clicked in the terminal directly to `shell.openExternal` without any protocol validation. When a user connects to a malicious SSH server, the attacker can print a crafted URI in the terminal output. If the victim clicks the link, `shell.openExternal` executes it using the operating system's default protocol handler. This can be abused to: - Trigger dangerous protocol handlers (`ms-msdt:`, `search-ms:`) for code execution - Open local files or network shares (`file://`, UNC paths) to leak NTLM hashes or exfiltrate data - Launch any installed application associated with a custom URI scheme An attacker who controls terminal output (e.g., via a malicious SSH server, compromised remote host, or malicious plugin rendering terminal content) can thus achieve arbitrary code execution or local file access on the victim's machine, requiring only that the victim clicks a displayed link. ### Patches As of electerm v3.7.9, no official patch has been released. Users should monitor the project’s [GitHub releases](https://github.com/electerm/electerm/releases) and [security page](https://github.com/electerm/electerm/security) for an update addressing this issue. ### Workarounds Until a patch is available: - Do not click on any links displayed in terminal sessions connected to untrusted servers. - If possible, disable hyperlink rendering in electerm's terminal settings. - Use a terminal multiplexer (e.g., tmux) or a separate terminal application that filters URI schemes when working with untrusted hosts. - Consider running electerm in a restricted environment (sandbox, AppArmor, SELinux) that limits the spawning of protocol handlers. ### 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 (confirmed on v3.7.9, Win10).

References

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