CVE-2026-24055Public exploitNetwork attack vector

Unauthorized Slack workspace linking via client-supplied projectId

Published Jan 22, 2026 · Updated Jan 22, 2026

Improper access control in Langfuse 3.89.0 through 3.146.0 allows remote attackers to link a Slack workspace to another project. The public /api/public/slack/install endpoint trusts a client-supplied projectId, carries it through OAuth, and stores callback installations for that project without authentication or authorization. Exposure requires Slack Prompt Automations: an existing automation sends managed prompt changes to the attacker's workspace, while a pre-registered integration also requires an authenticated user to select it.

CVSS severity6.3
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Langfuse 3.89.0 through 3.146.0 allows remote attackers to link a Slack workspace to another project. The public /api/public/slack/install endpoint trusts a client-supplied projectId, carries it through OAuth, and stores callback installations for that project without authentication or authorization. Exposure requires Slack Prompt Automations: an existing automation sends managed prompt changes to the attacker's workspace, while a pre-registered integration also requires an authenticated user to select it.

The record

CVE
CVE-2026-24055
Published
Jan 22, 2026
Updated
Jan 22, 2026
Vendor
Langfuse
Product
Langfuse
Classifications
CWE-862, CWE-284, T1567
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.89.0, < 3.147.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Langfuse · Langfuseversion=>= 3.89.0, < 3.147.0

Published CVSS scores

6.3GitHub, Inc.CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
5.3NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
CWE-284Improper Access Control
T1567Exfiltration Over Web Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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