CVE-2026-14541
mcp-toolbox Google OAuth provider skips audience validation, allowing token misuse
Is CVE-2026-14541 being exploited?
Not confirmed. CVE-2026-14541 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.23% probability of exploitation in the next 30 days.
How severe is CVE-2026-14541?
CVE-2026-14541 is rated High. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-14541?
Yes. A fix has been recorded for CVE-2026-14541. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-14541 affect?
CVE-2026-14541 affects Google mcp-toolbox 1.4.0, mcp-toolbox Google OAuth provider, Services using mcpEnabled:true without audience/clientId. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-14541?
Set explicit audience/clientId or disable mcpEnabled; apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authentication bypass: any valid Google OAuth access token may be accepted, granting unauthorized access to protected tools and data backends.
Immediate action required
- affected1.4.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.