CVE-2026-56274
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.
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
- CISA KEV
- Not listed
- Weakness
- CWE-78
- Affected
- flowiseai/flowise
- Source
- disclosure@vulncheck.com
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. Refreshed daily.