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Vulnerabilities

Vulnerability · 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.

Published Feb 21, 2026 · catalog updated Jun 17, 2026 · eBay API MCP Server

Check if you run it

No confirmed exploitation is on record for CVE-2026-27203. EPSS is 0.50%. Act only if a listed version of eBay API MCP Server is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (eBay API MCP Server).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.50%
Remediation
Advisory link
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-27203

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27203. EPSS is 0.50%. Act only if a listed version of eBay API MCP Server is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-15; CWE-74: Injection. EPSS 0.50%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 21, 2026 · NIST NVD

    Detected

    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 validati

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 validati

Sources

  • CVE.orgVulnerability recordCVE-2026-27203

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27203

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-27203

    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 f

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.