CVE-2026-56274

Name: CVE-2026-56274
Creator: NVD / NIST
Published: 2026-06-23T13:16:45.083+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.7/10EPSS 2.68%

Last modified Jun 25, 2026

CVE-2026-56274 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. 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 --yes' is not blocked while only '-y' is) and the validateArgsForLocalFileAccess checks, resulting in execution of arbitrary commands on the Flowise host.. EPSS estimates a 2.68% chance of exploitation in the next 30 days.

Description

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 --yes' is not blocked while only '-y' is) and the validateArgsForLocalFileAccess checks, resulting in execution of arbitrary commands on the Flowise host.

Metrics

CVSS 3.1

9.9/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS 4.0

8.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

2.68%

83.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-78

Affected Software

Vendor	Product	Versions
Flowiseai	Flowise	< 3.1.2

References

https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-m99r-2hxc-cp3qExploit, Third Party Advisory
https://www.vulncheck.com/advisories/flowise-remote-code-execution-via-mcp-security-bypass-in-validatecommandflags-and-validateargsforlocalfileaccessThird Party Advisory
https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-m99r-2hxc-cp3qExploit, Third Party Advisory

Timeline

Published: Jun 23, 2026
Last Modified: Jun 25, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-56274?

How severe is CVE-2026-56274?

CVE-2026-56274 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 2.68% probability of exploitation in the next 30 days.

How do I fix CVE-2026-56274?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-56274?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST