Langflow Unauthenticated Access via /build_public_tmp Causes Data Leak and DoS (CVE-2026-10560)

Vulnerability Overview Langflow OSS contains an unauthorized access vulnerability in the route endpoint. This vulnerability allows attackers to access any without authentication or authorization checks. Specific impacts include: 1. GET /build_public_tmp/{job_id}/events (chat.py:758): Streams real-time events for any stream, exposing customer prompts, LLM responses, API keys, internal RAG pipeline documents, and server-side Python tracebacks, thereby revealing the file system layout. 2. POST /build_public_tmp/{job_id}/cancel (chat.py:780): Cancels any in-progress build, enabling repeated denial-of-service attacks against a targeted tenant. Both endpoints rely on , lookup, and checks. However, downstream assistants and accept only without performing compensating authorization controls. Scope of Impact Affected Product: Langflow OSS Affected Versions: 1.0.0-1.9.6 Operating Systems: Windows, Mac OS, Linux Remediation IBM strongly recommends immediate resolution by upgrading Langflow OSS to version 1.10.0. Proof of Concept (POC) Code Additional Information CVE ID: CVE-2026-10560 CWE: CWE-287: Improper Authentication CVSS Source: IBM CVSS Base Score: 8.2 CVSS Vector: [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N] Reference Links Complete CVSS v3 Guide On-line Calculator v3 Related Resources IBM Secure Engineering Web Portal IBM Product Security Incident Response Blog Change History 25 Jun 2026: Initial Publication Disclaimer According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard" designed to convey vulnerability severity and help determine the urgency and priority of response efforts. IBM provides CVSS scores "as is" and makes no express or implied warranties. Customers are responsible for assessing the impact of any actual or potential security vulnerabilities. IBM regularly updates component records for products and services included in its inventory. As part of this effort, IBM identifies previously undisclosed vulnerabilities. For older CVE dates, IBM does not indicate that the referenced product has been used by IBM since that date, nor that IBM was aware of the vulnerability on that date. We are working to raise awareness of relevant vulnerabilities as we learn of them. The referenced "Affected Products and Versions" are intended to include only IBM-supported products and versions that have not reached end-of-life. Consequently, unsupported or extended-support products and versions not referenced in this document do not constitute IBM's assurance that they are unaffected by the vulnerability. Referencing one or more unsupported versions does not obligate IBM to fix unsupported or extended-support products or versions.

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Langflow Unauthenticated Access via /build_public_tmp Causes Data Leak and DoS (CVE-2026-10560)