Quick answers
- Is CVE-2026-14541 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-14541 being exploited in the wild.
- How severe is CVE-2026-14541?
- Informational severity, with a CVSS score of 8, published 31 July 2026.
- Which products and versions are affected?
- Google MCP Toolbox 1.4.0.
- Is there a fix for CVE-2026-14541?
- A patch was published on 2026-06-18: Fix merged in GitHub PR #3450 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-14541 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-14541?
- Check whether you run Google MCP Toolbox at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. The root cause is located in the ValidateMCPAuth pipeline, which skips audience validation for opaque tokens when the Google authService is initialized with mcpEnabled: true but lacks an explicitly defined audience or clientId. An unauthenticated remote attacker can exploit this by presenting a valid Google OAuth access token minted for a different, unrelated application. The toolbox will incorrectly accept these tokens, granting the attacker unauthorized access to protected tools and data backends. A fix has been merged into the main branch to enforce mandatory audience or clientId configuration.
Affected products
- Google mcp-toolbox 1.4.0
Timeline
- 2026-06-18: patched: Fix merged in GitHub PR #3450
- 2026-07-31: advisory: CVE published to NVD