CVE-2026-24055 — Langfuse Slack OAuth Installation Endpoint Lacks Authentication, Enabling Arbitrary Project Linking
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 project…
Published: 2026-01-22 · CVSS: 6.3 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7