CVE-2026-27203CWE-15CWE-74

eBay API MCP Server Affected by Environment Variable Injection

High · published February 20, 2026

CVSS v3.1
8.3
EPSS
1%
Percentile
45.0
In the wild
Unconfirmed
What it is

eBay API MCP Server is an open source local MCP server providing AI assistants with comprehensive access to eBay's Sell APIs. All versions are vulnerable to Environment Variable Injection through the updateEnvFile function. 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. An attacker can inject arbitrary environment variables into the .env file. This could lead to configuration overwrites, Denial of Service, and potential RCE. There was no fix for this issue at the time of publication.

The record
Technical detail
CVSS v3.1
8.3 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00546 · 45.0th percentile
Weaknesses
CWE-15 · External Control of System or Configuration Setting; CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Published
2026-02-20T23:30Z
EPSS history
Timeline
  • 20 FEB 23:30Z
    eBay API MCP Server Affected by Environment Variable Injection
    cvelistv5