Description

IBM Langflow OSS 1.0.0 through 1.11.1 could allow a remote attacker to execute arbitrary code due to improper enforcement of security restrictions on the A2A public endpoint.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-28T22:16:47.357Z",
  "pubdate": "2026-08-28T22:16:47.357Z",
  "executiveSummary": "IBM Langflow OSS, specifically versions 1.0.0 through 1.11.1, contains a critical vulnerability involving improper security enforcement on the A2A (Application-to-Application) public endpoint.\nThe vulnerability is classified as a Remote Code Execution (RCE) flaw, which allows unauthenticated remote attackers to execute arbitrary system commands on the host server.\nThis issue poses a severe security risk, as it permits full system compromise, data exfiltration, and lateral movement within the network infrastructure.\nThe exploitation does not require prior authentication, making it highly accessible to external threat actors targeting the public-facing API surface of the application.\nOrganizations utilizing Langflow versions within the specified range are at immediate risk of exploitation and should prioritize remediation efforts to prevent unauthorized access and execution of malicious code.\nThe flaw stems from a lack of validation or authorization controls on a specific interface intended for internal or automated use, effectively exposing dangerous backend capabilities to public network requests.",
  "technicalDetails": "The vulnerability exists within the A2A public endpoint functionality of IBM Langflow OSS, which fails to adequately sanitize or authorize incoming requests before processing them. The root cause is a deficiency in the security access controls applied to this specific endpoint, which should have been restricted to authenticated or internal communications only.\nBy targeting the A2A public endpoint, an unauthenticated attacker can submit specially crafted requests designed to bypass existing security logic. Because the endpoint does not properly validate the inputs or ensure that the requesting entity has appropriate authorization, it processes the malicious payload as a legitimate administrative or system command.\nThe attack flow typically involves the following steps: First, the attacker identifies the reachable A2A endpoint on the public-facing instance of Langflow. Second, the attacker constructs an HTTP request containing a payload designed to leverage the application's underlying execution environment. Third, the request is dispatched to the endpoint, which fails to enforce session or token validation. Fourth, the application backend interprets the payload, leading to the execution of arbitrary commands with the privileges of the service account running the Langflow process.\nThe scope of impact is critical, as successful execution allows the attacker to gain full control over the host environment. Once initial execution is achieved, the attacker may perform reconnaissance, escalate privileges, install persistent backdoors, or exfiltrate sensitive data stored within the Langflow environment, such as configuration secrets, workflow data, or API keys used for downstream integrations.\nThe vulnerability affects all versions of IBM Langflow OSS from 1.0.0 up to and including 1.11.1. Given that the A2A endpoint is public by design or by default configuration in these versions, the attack surface is significant. No authentication is required to interact with the vulnerable component, meaning the attack does not require a compromised user account or valid API credentials to initiate the exploit chain. The post-exploitation behavior is limited only by the permissions of the underlying OS user, making this a high-severity security oversight in the handling of external API communication."
}