CVE-2026-67531
Sandbox escape in FrontMCP <1.5.7 enables remote code execution
Is CVE-2026-67531 being exploited?
Not confirmed. CVE-2026-67531 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 0.57% probability of exploitation in the next 30 days.
How severe is CVE-2026-67531?
CVE-2026-67531 is rated Critical with a CVSS score of 9.3. 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-2026-67531?
Yes. A fix has been recorded for CVE-2026-67531. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-67531 affect?
CVE-2026-67531 affects FrontMCP <1.5.7, TypeScript/Node apps using FrontMCP, Servers exposing tools/call, Zod v4 integrations. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-67531?
Upgrade to FrontMCP >=1.5.7, disable public DEFAULT_AUTH_OPTIONS, and rotate exposed secrets
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution as the server user; attackers can read OAuth/JWT/session keys, DB credentials and cloud metadata.
Immediate action required
- affected< 1.5.7
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.