CVE-2025-9799: Langfuse

Medium severity, CVSS 5.0. EPSS: 0.3% chance of exploitation in the next 30 days.

A security flaw has been discovered in Langfuse up to 3.88.0. Affected by this vulnerability is the function promptChangeEventSourcing of the file web/src/features/prompts/server/routers/promptRouter.ts of the component Webhook Handler. Performing manipulation results in server-side request forgery. The attack may be initiated remotely. A high degree of complexity is needed for the attack. The exploitation appears to be difficult. The exploit has been released to the public and may be exploited.

Affected products

• Langfuse Langfuse: up to and including 3.88.0

Published 2025-09-01. Last modified 2026-06-17.