GHSA-8fcc-w5hv-4gxv
Suggest an improvement- Source
- https://github.com/advisories/GHSA-8fcc-w5hv-4gxv
- Import Source
- https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-8fcc-w5hv-4gxv/GHSA-8fcc-w5hv-4gxv.json
- JSON Data
- https://api.osv.dev/v1/vulns/GHSA-8fcc-w5hv-4gxv
- Aliases
- Published
- 2026-06-18T15:32:01Z
- Modified
- 2026-06-25T19:56:37Z
- Severity
-
- 9.3 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N CVSS Calculator
- Summary
- googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)
- Details
-
An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox.
When verifying an unparsed opaque token via an OAuth 2.0 introspection endpoint (RFC 7662), the toolbox decodes the response into an introspectResp struct where the Active field is declared as a pointer to a boolean (*bool). The code only explicitly rejects a token if the response contains a populated active field set to false (if introspectResp.Active != nil && !*introspectResp.Active). If an introspection endpoint responds with a payload that completely omits the mandatory active key, the internal variable remains nil, causing the conditional check to short-circuit. As a result, Toolbox accepts authorization tokens missing the "active" field, granting access to protected tools and underlying data sources.
- Database specific
{ "cwe_ids": [ "CWE-287" ], "github_reviewed": true, "github_reviewed_at": "2026-06-19T16:58:21Z", "nvd_published_at": "2026-06-18T14:17:20Z", "severity": "CRITICAL" }- References
Affected packages
Go / github.com/googleapis/mcp-toolbox
Package
- Name
- github.com/googleapis/mcp-toolbox
- View open source insights on deps.dev
- Purl
- pkg:golang/github.com/googleapis/mcp-toolbox