Cyber Resilience

CVE-2026-55255

CriticalPublic PoC

Published: 23 June 2026

Published
23 June 2026
Modified
24 June 2026
KEV Added
Patch
CVSS Score v3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
EPSS Score 0.0023 14.2th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-55255 is a critical-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Langflow Langflow. Its CVSS base score is 9.9 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 14.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability details

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.2, 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…

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victim's flow ID in the request. This vulnerability is fixed in 1.9.2.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

IDOR in public-facing API endpoint directly enables unauthorized flow execution by exploiting the application vulnerability.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Affected Assets

langflow
langflow
≤ 1.9.2

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-639

Per-request decision making makes it harder to bypass authorization using user-controlled keys without proper validation in the decision process.

addresses: CWE-639

Consistent enforcement of approved authorizations makes bypassing via user-controlled keys ineffective.

References