🛡️ CVE-2026-49253 — electerm

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-22 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

electerm has Path Traversal in Zmodem and Trzsz Download Filename Handling

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 - getUniqueFilePath() at line 559, openSaveFile() callback, and savedFilePaths mapping

Patches

  • https://github.com/electerm/electerm/commit/fde153d677a170c5816368f6586647f3af4ef284

Workarounds

If upgrading is not immediately possible, users can mitigate this vulnerability by:

1. Only connecting to trusted SSH servers

2. Rejecting or canceling any incoming Zmodem or Trzsz file transfers from untrusted sources

3. Avoiding the use of Zmodem (sz/rz) and Trzsz (trz/tsz) commands on untrusted servers

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability low.

Weakness class

CVE-2026-49253 is classified as CWE-22: Path Traversal. A file path built from user input is not confined to the intended directory, letting an attacker reach files elsewhere on the filesystem.

Affected software

CVE-2026-49253 is recorded against 1 package.

  • electerm

Timeline and source

Published on 2 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
github.com (Web)
github.com (Package)

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
CWE CWE-22
Public Exploit ✅ No
Source OSV
Published 2026-07-02
Updated 2026-08-12
Modified 2026-07-02
Fix URL N/A

Affected Packages

Software From version Fixed in
electerm — —

Similar Threats

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