VulnerabilityAnalyzed

CVE-2026-56274

HIGH 8.7EPSS 7.52%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (7.52%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0: 8.7 HIGHCVSS: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/M
EPSS: 7.52% probability · 94th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-78
Affected: flowiseai/flowise
Source: disclosure@vulncheck.com

EPSS trend

EPSS 7.5% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.