CISA KEV Catalog Addition Including Langflow Authorization Bypass

Technical Analysis

CVE-2026-55255 is described as an 'Authorization Bypass Through User-Controlled Key' vulnerability in Langflow, a low-code framework for building LLM-powered agent and RAG pipelines. This class of bug typically allows an attacker to supply or manipulate a key/identifier (e.g., API key, session token, or object reference) that the server trusts without proper server-side validation, enabling access to other users' flows, credentials, or backend resources. In an agentic context, this could allow an attacker to view or modify agent workflow definitions, exfiltrate embedded API keys/secrets used by connected tools or LLM providers, or inject malicious logic into a shared pipeline that other users/agents execute. Because Langflow orchestrates calls to external tools, models, and data sources, a bypass at the authorization layer crosses from a simple access-control flaw into a supply-chain-style risk affecting every downstream agent or tool invoked by the compromised flow. The KEV listing confirms active exploitation in the wild, elevating urgency beyond a theoretical framework bug.

Affected Systems

Langflow, JoomShaper SP Page Builder, Joomlack Page Builder

Detection Signatures

• Unexpected access to Langflow flow IDs/objects not owned by the requesting user or API key
• API requests to Langflow endpoints with manipulated or guessed key/ID parameters
• Anomalous retrieval of stored credentials or flow configs via authorization-sensitive endpoints
• Log entries showing cross-tenant or cross-user flow access in multi-tenant Langflow deployments
• Unexplained modification of agent/tool pipeline definitions

Remediation Steps

1. 1

   Patch Langflow immediately

   Upgrade to the fixed Langflow version addressing CVE-2026-55255 per vendor advisory; treat as urgent given confirmed active exploitation and KEV listing.

2. 2

   Audit authorization logic

   Review Langflow deployment for any user-controlled keys/IDs used in authorization decisions; ensure server-side ownership checks, not client-supplied identifiers, gate access to flows and secrets.

3. 3

   Rotate exposed credentials

   Rotate any API keys, LLM provider tokens, or connected tool credentials stored within Langflow flows that may have been exposed via the bypass.

4. 4

   Restrict public exposure

   Per BOD 26-04 guidance, prioritize remediation on publicly exposed Langflow instances that grant significant control post-exploitation; restrict network access where possible.

5. 5

   Check for prior compromise

   Review logs for signs of exploitation prior to patching, consistent with BOD 26-04 requirements for compromise assessment before/after patch application.