Staging Environment: Content and features may be unstable or change without notice.
Advisory details: github_osv / GHSA-38j7-23hf-9mhc
Advisory ID github_osv/GHSA-38j7-23hf-9mhc
Aliases CVE-2026-49253
Summary 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
Status Published
Exploitability 0.5
Weighted Severity 6.4
Risk 3.2
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (1)
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
System Score Found at
cvssv3.1 7.1 https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-38j7-23hf-9mhc/GHSA-38j7-23hf-9mhc.json
generic_textual HIGH
Reference id Reference type URL
https://github.com/electerm/electerm
https://github.com/electerm/electerm/commit/fde153d677a170c5816368f6586647f3af4ef284
https://github.com/electerm/electerm/security/advisories/GHSA-38j7-23hf-9mhc
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L Found at https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-38j7-23hf-9mhc/GHSA-38j7-23hf-9mhc.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-08-21T19:31:22Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/49xxx/CVE-2026-49253.json

Source Advisory: vulnrichment/CVE-2026-49253

View SSVC decision tree 
[{'Exploitation': 'poc'},
 {'Automatable': 'no'},
 {'Technical Impact': 'partial'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]