How severe is CVE-2026-55255?

CVE-2026-55255 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2026-55255 being actively exploited?

Yes. CVE-2026-55255 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-07-07, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2026-55255?

CVE-2026-55255 affects Langflow. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-55255?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2026-55255 have an EU (EUVD) identifier?

Yes. CVE-2026-55255 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38517.

When was CVE-2026-55255 published?

CVE-2026-55255 was published on 2026-06-23 and last updated on 2026-07-08.

CVE-2026-55255

CVE-2026-55255 is a high-severity vulnerability in Langflow with a CVSS 3.x base score of 8.4. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-07-07). The underlying weakness is classified as CWE-639.

Key facts

Severity: High (CVSS 3.x base score 8.4)
EPSS exploit prediction: 29% (98th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-07-07)
EU (EUVD) id: EUVD-2026-38517
Weakness: CWE-639
Affected product: Langflow
Published: 2026-06-23
Last modified: 2026-07-08

Description

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.

Frequently asked questions

What is CVE-2026-55255?: Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.
How severe is CVE-2026-55255?: CVE-2026-55255 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2026-55255 being actively exploited?: Yes. CVE-2026-55255 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-07-07, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-55255?: CVE-2026-55255 affects Langflow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-55255?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2026-55255 have an EU (EUVD) identifier?: Yes. CVE-2026-55255 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38517.
When was CVE-2026-55255 published?: CVE-2026-55255 was published on 2026-06-23 and last updated on 2026-07-08.

References

Affected products (1)

cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*

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