electerm has Path Traversal in Zmodem and Trzsz Download Filename Handling

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L

EPSS

• CVE-2026-49253: 0.44% estimated exploitation activity in the next 30 days; percentile 38.24 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact A path traversal vulnerability exists in the Zmodem and Trzsz file download handlers in electerm. When receiving files via Zmodem or Trzsz protocols, electerm uses the remote-supplied filename directly in path.join() with the user-selected download directory without sanitization. A malicious SSH server or remote shell process can send a specially crafted filename such as ../escaped.txt to escape the user-selected download directory and write files to arbitrary locations on the user's filesystem, subject to process permissions. Attack scenario: 1. User connects to a malicious SSH server 2. Attacker initiates a Zmodem or Trzsz file transfer 3. Attacker supplies a traversal filename (e.g., ../../.bashrc, ../escaped.txt) 4. User accepts the transfer and selects a download directory 5. File is written outside the selected directory, potentially overwriting sensitive files Affected components: - src/app/server/zmodem.js - prepareReceiveFile() at line 736 - src/app/server/trzsz.js -…

Published by the source

2 Jul 2026, 19:20 UTC

Last modified by the source

2 Jul 2026, 19:41 UTC

Source last checked

26 Oct 2026, 12:56 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-38j7-23hf-9mhc

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-38j7-23hf-9mhc

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# Patch Next advisory brief: CVE-2026-49253

Advisory: electerm has Path Traversal in Zmodem and Trzsz Download Filename Handling
IDs: CVE-2026-49253, GHSA-38j7-23hf-9mhc
Record: https://patchnext.com/advisories/cve-2026-49253 (revision 2, source checked 26 Oct 2026, 12:56 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: electerm 3.11.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm electerm: affected <= 3.11.0; fixed in 3.11.11

## Suggested inspection (read-only)
- `npm ls electerm --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on electerm.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-38j7-23hf-9mhc (OSV record GHSA-38j7-23hf-9mhc lists affected ranges: npm electerm >=0 <3.11.11 (fixed))
- Verified: https://github.com/advisories/GHSA-38j7-23hf-9mhc (GitHub-reviewed advisory GHSA-38j7-23hf-9mhc lists affected ranges: npm electerm >=0 <=3.11.0)

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