CVE-2026-17627 Overview
CVE-2026-17627 is an improper authorization vulnerability [CWE-639] affecting IBM Langflow OSS versions 1.0.0 through 1.10.2. A remote authenticated attacker can exploit the flaw to access sensitive information and inject arbitrary messages into workflow history. The issue stems from missing authorization checks that fail to validate whether the requesting user owns the targeted workflow resource. Langflow is a visual framework for building AI agent workflows, making it a common component in enterprise generative AI pipelines. Successful exploitation compromises confidentiality of workflow data and integrity of stored conversation history.
Critical Impact
Authenticated attackers can read sensitive workflow data belonging to other users and tamper with workflow message history, undermining the integrity of AI-driven business processes.
Affected Products
- Langflow OSS versions 1.0.0 through 1.10.2
- Deployments on Linux
- Deployments on Apple macOS and Microsoft Windows
Discovery Timeline
- 2026-09-04 - CVE-2026-17627 published to NVD
- 2026-09-09 - Last updated in NVD database
Technical Details for CVE-2026-17627
Vulnerability Analysis
The vulnerability is classified as Authorization Bypass Through User-Controlled Key [CWE-639]. Langflow exposes API endpoints that operate on workflow objects and their message history. These endpoints authenticate the caller but do not verify that the authenticated user is authorized to access the specific resource identifier supplied in the request. An attacker with any valid account can substitute another user's workflow identifier and receive that user's data in the response. The same authorization gap allows attackers to append or modify messages in another user's workflow history, corrupting agent conversation context.
Root Cause
The root cause is missing object-level authorization on workflow and message endpoints. The application relies on the presence of a valid session or API token as a sufficient authorization signal. It does not enforce a per-object ownership check that ties the requested resource identifier to the caller. This is a common pattern in applications that rapidly evolve API surface area without a centralized authorization layer.
Attack Vector
Exploitation requires network access to a Langflow instance and low-privileged authenticated credentials. No user interaction is required. An attacker enumerates or guesses workflow identifiers, then issues API requests referencing those identifiers. The server returns the requested workflow content or accepts injected messages without verifying ownership. In multi-tenant deployments, this allows one tenant to read prompts, credentials embedded in workflow nodes, and prior conversation content belonging to other tenants.
No public proof-of-concept code has been released for this issue. Refer to the IBM Support Document for vendor-provided technical detail.
Detection Methods for CVE-2026-17627
Indicators of Compromise
- Access logs showing a single authenticated user requesting workflow identifiers associated with multiple distinct account owners.
- Unexpected POST or PATCH requests to workflow message endpoints from accounts that do not own the target workflow.
- Sequential enumeration patterns against workflow identifier paths, suggesting resource discovery.
Detection Strategies
- Correlate API request identifiers with the authenticated principal and alert when the principal does not match the workflow owner recorded in application state.
- Baseline normal per-user workflow access volume and flag deviations that suggest cross-tenant enumeration.
- Inspect workflow message history for entries whose author metadata does not match the authenticated session that created them.
Monitoring Recommendations
- Forward Langflow application and reverse proxy logs to a centralized analytics platform for cross-user correlation.
- Monitor for anomalous read volume against /api/v1/flows and message endpoints on a per-account basis.
- Track authentication events alongside object access to identify low-privileged accounts probing high-value workflows.
How to Mitigate CVE-2026-17627
Immediate Actions Required
- Upgrade Langflow OSS to a fixed release above 1.10.2 as identified in the IBM Support Document.
- Restrict network exposure of Langflow instances to trusted networks and authenticated reverse proxies until patched.
- Rotate any credentials, API keys, or secrets referenced inside workflow nodes that may have been exposed.
- Audit workflow message history for injected or unexpected entries and restore from backup where integrity is in doubt.
Patch Information
IBM has published remediation guidance in the IBM Support Document for CVE-2026-17627. Administrators should apply the vendor-supplied upgrade path for Langflow OSS 1.0.0 through 1.10.2 and validate that object-level authorization is enforced after the update.
Workarounds
- Limit account provisioning on shared Langflow instances and segregate tenants across separate deployments where feasible.
- Place Langflow behind an authenticating reverse proxy that enforces per-user access control lists against workflow identifiers.
- Disable or restrict endpoints that expose workflow message history until the upgrade is applied.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
