Unauthenticated Access in IBM Langflow OSS

Executive Summary

CVE-2026-10560 is a security vulnerability in IBM Langflow OSS versions 1.0.0 through 1.9.6 that involves missing authentication on certain API endpoints.

Specifically, the endpoints /api/v1/build_public_tmp/{job_id}/events and /api/v1/build_public_tmp/{job_id}/cancel do not require authentication or authorization, allowing an unauthenticated attacker to access sensitive build event data or cancel jobs by knowing a valid job identifier.

The GET endpoint streams live build events, potentially exposing sensitive information such as customer prompts, large language model (LLM) responses, API keys, internal documents, and filesystem paths.

The POST endpoint allows attackers to cancel in-progress flow builds, which can cause denial-of-service conditions.

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Impact Analysis

This vulnerability can have significant impacts including information disclosure and denial of service.

• Information Disclosure: Attackers can read sensitive build event data such as customer prompts, LLM responses, API keys, internal documents, and filesystem paths without authentication.
• Denial of Service: Attackers can cancel active jobs by sending cancellation requests with valid job identifiers, disrupting normal operations.

Because the vulnerability requires no authentication and has a high CVSS score of 8.2, it poses a serious security risk.

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Detection Guidance

This vulnerability can be detected by attempting to access the vulnerable endpoints without authentication to see if sensitive data or job cancellation is possible.

• Use a command like: curl -v GET http://<langflow-server>/api/v1/build_public_tmp/<job_id>/events to check if build event data is accessible without authentication.
• Use a command like: curl -v -X POST http://<langflow-server>/api/v1/build_public_tmp/<job_id>/cancel to test if job cancellation is possible without authentication.

If these commands succeed without authentication, it indicates the presence of the vulnerability.

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Mitigation Strategies

The immediate step to mitigate this vulnerability is to upgrade IBM Langflow OSS to version 1.10.0 or later, where the issue is fixed.

No workarounds are available, so upgrading is the only recommended mitigation.

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Compliance Impact

The vulnerability allows unauthenticated attackers to access sensitive data such as customer prompts, LLM responses, API keys, internal documents, and filesystem paths. This exposure of sensitive information could lead to non-compliance with data protection regulations like GDPR and HIPAA, which require protection of personal and sensitive data against unauthorized access.

Additionally, the ability to cancel in-flight flow builds without authorization could disrupt service availability, potentially impacting compliance with standards that mandate system integrity and availability.

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