Flowise Flaw Lets Unauthenticated Attackers Hijack Sessions and Inject Flow Properties
Emerging Technology Risk · 3 sources · Updated 3mo ago · First seen Aug 4, 2026
A high-severity vulnerability in Flowise, tracked as CVE-2026-69258, allows unauthenticated attackers to tamper with the execution context of public chatflows through the POST /api/v1/prediction/:id endpoint. In affected versions before 3.1.3, the application accepted an overrideConfig object and merged it into internal flowConfig and flowData structures without enforcing apiOverrideStatus, enabling attackers to overwrite values such as sessionId, chatId, and chatHistory and bypass session isolation.
The flaw can let attackers access, pollute, or hijack other users’ conversations and inject arbitrary properties into the $flow.* namespace used by flow nodes, including variables that may influence SQL queries, webhooks, and API integrations. The issue is rated CVSS 8.8 and mapped to CWE-639 and CWE-915; while it does not directly provide operating-system-level remote code execution, it can break logical security boundaries and corrupt routing, prompt history, and downstream workflow behavior. Flowise patched the issue in version 3.1.3, and users are advised to upgrade.
