GitHub Advisoryadvisory · npm

GHSA-97rm-xj73-33jh eBay API MCP Server Affected by Environment Variable Injection

HIGH Published 2026-02-19 Modified 2026-02-23 Official page ↗
Aliases
CVE-2026-27203
Ecosystem
npm
Packages
ebay-mcp
Severity
High
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
Weaknesses
CWE-15, CWE-74
Reviewed
2026-02-19

Affected packages

• npm ebay-mcp: <= 1.7.2 (no fix yet)

Description

The `ebay_set_user_tokens` tool allows updating the `.env` file with new tokens. The `updateEnvFile` function in `src/auth/oauth.ts` blindly appends or replaces values without validating them for newlines or quotes. This allows an attacker to inject arbitrary environment variables into the configuration file. Impact An attacker can inject arbitrary environment variables into the `.env` file. This could lead to: • Configuration Overwrites: Attackers can overwrite critical settings like `EBAY_REDIRECT_URI` to hijack OAuth flows. • Denial of Service: Injecting invalid configuration can prevent the server from starting. • Potential RCE: In some environments, controlling environment variables (like `NODE_OPTIONS`) can lead to Remote Code Execution. Found with MCPwner 🕶

Related

Alias · CVE (1)

  • CVE-2026-27203 eBay API MCP Server is an open source local MCP server providing AI assistants with comprehensive access to eBay's Sell APIs. vulnerability

Weakness · CWE (2)

  • CWE-15 External Control of System or Configuration Setting weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component weakness

References