CVE-2025-9799 Langfuse Webhook promptRouter.ts promptChangeEventSourcing server-side request forgery

Low 2.3 Published 1 Sep 2025 Updated 2 Sep 2025

Remote attackers can exploit a server-side request forgery flaw in Langfuse's webhook handler to access internal resources or bypass security controls.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2025-9799?

CVE-2025-9799 is a low-severity server-side request forgery vulnerability in Langfuse, published on 1 Sep 2025. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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.

Weakness: CWE-918

Which versions are affected by CVE-2025-9799?

It affects 1 product.

Products include Langfuse Langfuse.

How do I fix CVE-2025-9799?

No fix has been published for CVE-2025-9799 yet. Limit exposure of the affected software until one is available.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2025-9799 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-9799 exists.

Sources

Also known as GHSA-6fxv-w47f-g229.