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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.

PUBLISHED Reserved 2026-01-20 | Published 2026-01-22 | Updated 2026-01-22 | Assigner GitHub_M




MEDIUM: 6.3CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Problem types

CWE-284: Improper Access Control

Product status

>= 3.89.0, < 3.147.0
affected

References

github.com/...ngfuse/security/advisories/GHSA-pvq7-vvfj-p98x

github.com/...ommit/3adc89e4d72729eabef55e46888b8ce80a7e3b0a

github.com/langfuse/langfuse/releases/tag/v3.147.0

langfuse.com/...agement/features/webhooks-slack-integrations

cve.org (CVE-2026-24055)

nvd.nist.gov (CVE-2026-24055)

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