What is the CVSS score of CVE-2026-27203?

CVE-2026-27203 has a CVSS 3.1 base score of 8.3 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of AI / ML are affected by CVE-2026-27203?

CVE-2026-27203 affects organizations using eBay API MCP Server, allowing attackers to inject malicious environment variables and potentially gain unauthorized access to eBay Sell APIs and connected…

How to fix or mitigate CVE-2026-27203?

Within 24 hours: Identify all systems running eBay API MCP Server and isolate them from production networks if possible; notify relevant business stakeholders. Within 7 days: Implement network segmentation to restrict API server access, disable the updateEnvFile function if not critical to operations, and audit recent environment variable changes for signs of compromise. Within 30 days: Establish a vendor communication protocol to track patch availability, conduct a comprehensive security review of API integrations, and develop an incident response plan specific to this vulnerability.

AI / ML CVE-2026-27203

HIGH

External Control of System or Configuration Setting (CWE-15)

2026-02-21 security-advisories@github.com

GHSA-97rm-xj73-33jh

Denial Of Service AI / ML

8.3

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

8.3 HIGH

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:04 vuln.today

CVE Published

Feb 21, 2026 - 00:16 nvd

HIGH 8.3

DescriptionGitHub Advisory

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.

AnalysisAI

eBay API MCP Server's ebay_set_user_tokens tool fails to validate environment variable inputs in the updateEnvFile function, allowing authenticated attackers to inject arbitrary variables into the .env configuration file. An attacker with login credentials can exploit this to overwrite existing configurations, trigger denial of service conditions, or achieve remote code execution through malicious environment variable injection. No patch is currently available for this vulnerability affecting all versions of the AI/ML product.

Technical ContextAI

exists in the updateEnvFile component. 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 in