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 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.
Affected Software
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Event History
Frequently Asked Questions
What is the severity of CVE-2026-24055?
CVE-2026-24055 is considered a critical vulnerability due to its potential for unauthorized access and project linking without authentication.
How do I fix CVE-2026-24055?
To fix CVE-2026-24055, upgrade Langfuse to version 3.147.0 or later, which includes the necessary security patches.
What is affected by CVE-2026-24055?
CVE-2026-24055 affects Langfuse versions 3.146.0 and below that employ the /api/public/slack/install endpoint without proper authentication.
Can I exploit CVE-2026-24055?
Yes, CVE-2026-24055 allows attackers to exploit the vulnerability by linking arbitrary projects without authorization.
Where can I find more information about CVE-2026-24055?
Additional details about CVE-2026-24055 are available in the security advisories and release notes on GitHub.