CVE-2026-73601
Authenticated RCE in Flowise Custom MCP node via stdio env vars (pre-3.1.3).
Is CVE-2026-73601 being exploited?
Not confirmed. CVE-2026-73601 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 0.88% probability of exploitation in the next 30 days.
How severe is CVE-2026-73601?
CVE-2026-73601 is rated Critical with a CVSS score of 9.0. 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-2026-73601?
Yes. A fix has been recorded for CVE-2026-73601. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-73601 affect?
CVE-2026-73601 affects Flowise < 3.1.3, Flowise Custom MCP node, Instances with CUSTOM_MCP_PROTOCOL=stdio, Deployments running python3 or node runtimes. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-73601?
Upgrade Flowise to >=3.1.3 or disable CUSTOM_MCP_PROTOCOL=stdio until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attackers can execute arbitrary system commands (RCE) by manipulating env vars or working directory, enabling full host compromise and data exfiltration.
Immediate action required
- affected< 3.1.3
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.