How severe is CVE-2026-56274?

CVE-2026-56274 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-56274 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-56274?

CVE-2026-56274 affects Flowiseai Flowise. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-56274?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-56274 have an EU (EUVD) identifier?

Yes. CVE-2026-56274 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38434.

When was CVE-2026-56274 published?

CVE-2026-56274 was published on 2026-06-23 and last updated on 2026-06-25.

CVE-2026-56274

CVE-2026-56274 is a critical-severity vulnerability in Flowiseai Flowise with a CVSS 3.x base score of 9.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
CVSS v4: 8.7
EPSS exploit prediction: 8% (94th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38434
Weakness: CWE-78
Affected product: Flowiseai Flowise
Published: 2026-06-23
Last modified: 2026-06-25

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.

Frequently asked questions

What is 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. 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.
How severe is CVE-2026-56274?: CVE-2026-56274 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-56274 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-56274?: CVE-2026-56274 affects Flowiseai Flowise. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-56274?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-56274 have an EU (EUVD) identifier?: Yes. CVE-2026-56274 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38434.
When was CVE-2026-56274 published?: CVE-2026-56274 was published on 2026-06-23 and last updated on 2026-06-25.

References

Affected products (1)

cpe:2.3:a:flowiseai:flowise:*:*:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

18.228.228.159 (ipv4-addr)
3.19.213.118 (ipv4-addr)
51.17.154.141 (ipv4-addr)