# CVE-2026-24055: Langfuse Slack OAuth Installation Endpoint Lacks Authentication, Enabling Arbitrary Project Linking

> CVE-2026-24055: Langfuse Slack OAuth Installation Endpoint Lacks Authentication, Enabling Arbitrary Project Linking. CVSS 5.3 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-24055
Last updated: 2026-06-17T10:22:31Z

- Published: 2026-01-22 03:07 UTC · Updated: 2026-06-17 10:22 UTC · Assigner: GitHub\_M
- CVSS: 5.3 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- EPSS: 0.43%, 37th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-284

## 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.

## Affected vendors and products

- langfuse: langfuse

## Tracked companies

- [Langfuse](https://rewindex.com/company/langfuse.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-24055)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-24055)
- [https://github.com/langfuse/langfuse/commit/3adc89e4d72729eabef55e46888b8ce80a7e3b0a](https://github.com/langfuse/langfuse/commit/3adc89e4d72729eabef55e46888b8ce80a7e3b0a)
- [https://github.com/langfuse/langfuse/releases/tag/v3.147.0](https://github.com/langfuse/langfuse/releases/tag/v3.147.0)
- [https://github.com/langfuse/langfuse/security/advisories/GHSA-pvq7-vvfj-p98x](https://github.com/langfuse/langfuse/security/advisories/GHSA-pvq7-vvfj-p98x)
- [https://langfuse.com/docs/prompt-management/features/webhooks-slack-integrations](https://langfuse.com/docs/prompt-management/features/webhooks-slack-integrations)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-24055 · Markdown: https://rewindex.com/cve/CVE-2026-24055.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-24055 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T04:04:42.872Z