CVE-2026-24055 Langfuse Slack OAuth Installation Endpoint Lacks Authentication, Enabling Arbitrary Project Linking
Unauthenticated attackers can link arbitrary Slack workspaces to Langfuse projects, enabling unauthorized access to or modification of prompt management integrations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-24055?
CVE-2026-24055 is a medium-severity missing authorization vulnerability in langfuse, published on 22 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Langfuse is an open source large language model engineering platform. In versions 3.146.0 and below, the /api/public/slack/install endpoint initiates Slack OAuth using a projectId provided by the client without authentication or authorization. The projectId is preserved throughout the OAuth flow, and the callback stores installations based on this untrusted metadata. This allows an attacker to bind their Slack workspace to any project and potentially receive changes to prompts stored in Langfuse Prompt Management. An attacker can replace existing Prompt Slack Automation integrations or pre-register a malicious one, though the latter requires an authenticated user to unknowingly configure it despite visible workspace and channel indicators in the UI. This issue has been fixed in version 3.147.0.
Which versions are affected by CVE-2026-24055?
It affects 1 product.
Products include Langfuse Langfuse.
How do I fix CVE-2026-24055?
No fix has been published for CVE-2026-24055 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-24055 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-24055 exists.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in langfuse
- CVE-2025-59305 Missing authorization in n/a
- CVE-2025-65107 Langfuse SSO Account Takeover via CSRF or phishing attack
- CVE-2026-41487 Missing authorization in langfuse
- CVE-2025-64504 Langfuse vulnerable to cross‑organization enumeration of member & invitation lists via project membership APIs
- CVE-2025-9799 Langfuse Webhook promptRouter.ts promptChangeEventSourcing server-side request forgery
Sources
Also known as GHSA-pvq7-vvfj-p98x.