Langfuse up to 3.146.x Slack install access control

Summaryinfo

A vulnerability, which was classified as critical, has been found in Langfuse up to 3.146.x. This affects an unknown function of the file /api/public/slack/install of the component Slack. Performing a manipulation results in access control. This vulnerability was named CVE-2026-24055. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Langfuse up to 3.146.x. This affects an unknown functionality of the file /api/public/slack/install of the component Slack. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-24055 since 01/20/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

Upgrading to version 3.147.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 3adc89e4d72729eabef55e46888b8ce80a7e3b0a is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• Langfuse

Version

• 3.146

License

• open-source

Website

• Product: https://github.com/langfuse/langfuse/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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