PatchTheCVECVE-2026-56274: Flowise before 3.1.2 contains multiple OS command injection vulnerabilities in the Custom MCP Server feature d
CVE-2026-56274 is a critical-severity flaw (CVSS 9.9) affecting flowise. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Flowise before 3.1.2 contains multiple OS command injection vulnerabilities in the Custom MCP Server feature due to incomplete command-flag validation and a regex bypass in local file access restrictions. An attacker with a Flowise account of any role, or API access with view/update permissions for chatflows, can configure a malicious MCP server to bypass the validateCommandFlags blocklist (for example, 'docker build' is not blocked, and 'npx --y
Why this priority
- Critical severity
- EPSS top 6%: very likely to be exploited
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.9 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 7.5% (top 6%) |
| CISA exploited list | No |
| Weakness | CWE-78 |
| Published | 2026-06-23 |
| Last modified | 2026-06-25 |
Last updated 2026-06-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Write-up: github.com/FlowiseAI/Flowise/security/advisories/GHSA-m99r-2hxc-cp3q
- Metasploit: Flowise MCP Server Remote Code Execution
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-56274?
flowise: upgrade to 3.1.2. Exact commands for each OS are on this page.
Is CVE-2026-56274 being exploited?
CVE-2026-56274 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-56274 affect?
CVE-2026-56274 affects flowise. Severity is critical (CVSS 9.9). Flowise before 3.1.2 contains multiple OS command injection vulnerabilities in the Custom MCP Server feature due to incomplete command-flag validation and a regex bypass in local file access restrictions. An attacker with a Flowise account
How urgent is CVE-2026-56274?
Priority 63/100. Critical severity; EPSS top 6%: very likely to be exploited; Public exploit reference
Software pages
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