CVE-2026-6542

Monitor API allows cross-user read of transaction logs and deletion of build data via flow_id

Published Apr 30, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
IBM Langflow OSS 1.0.0 through 1.8.4 could allow any user to supply a flow_id to read transaction logs and vertex build data belonging to other users, and to delete persisted vertex build data for another user's flow.

Analysis

AI-generated

Technical impact

IBM Langflow OSS versions 1.0.0 through 1.8.4 contain a flaw in the Monitor API that allows any user with API access to supply a flow_id and retrieve transaction logs and vertex build data belonging to another user. The same mechanism can also delete a victim’s persisted vertex build data. The weakness arises from insufficient authorization checks on the API endpoint (CWE‑639). The consequence is a breach of confidentiality and integrity for other users’ data, potentially leading to service disruption. Based on the description, it is inferred that an attacker must have API access to exploit this flaw.

Affected Systems

The vulnerability affects IBM Langflow OSS deployments running versions 1.0.0 to 1.8.4. IBM does not list additional affected sub‑versions, so older major releases that are not explicitly mentioned are presumed unaffected. The issue is present in the open‑source edition of Langflow and is illustrated by the listed CPE entries for 1.0.0 and 1.8.4.

Risk and Exploitability

The CVSS score of 6.5 indicates a moderate severity. The EPSS score of < 1% indicates a very low exploitation probability. The weakness is an authorization lapse (CWE‑639) that is easily exploitable by any user with API access; based on the description, it is inferred that the attacker must have API access to trigger the exploit. The vulnerability is not listed in the CISA KEV catalog, so it is presently not known to be widely exploited. The potential impact is significant for confidentiality and integrity of other users’ data.

Remediation

Vendor Solution

IBM recommends addressing the vulnerability now by upgrading to Langflow OSS 1.9.0 or newer:  https://github.com/langflow-ai/langflow


OpenCVE Recommended Actions

  • Upgrade to Langflow OSS 1.9.0 or newer as recommended by IBM
  • If an upgrade is not immediately possible, restrict or disable the Monitor API endpoint for users who do not require it
  • Audit existing build data and logs to ensure no sensitive information remains exposed, and delete any orphaned or unnecessary data

Generated by OpenCVE AI on May 2, 2026 at 08:04 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Langflow
Langflow langflow
CPEs cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*
Vendors & Products Langflow
Langflow langflow
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description IBM Langflow OSS 1.0.0 through 1.8.4 could allow any user to supply a flow_id to read transaction logs and vertex build data belonging to other users, and to delete persisted vertex build data for another user's flow.
Title Monitor API allows cross-user read of transaction logs and deletion of build data via flow_id
First Time appeared Ibm
Ibm langflow Oss
Weaknesses CWE-639
CPEs cpe:2.3:a:ibm:langflow_oss:1.0.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:langflow_oss:1.8.4:*:*:*:*:*:*:*
Vendors & Products Ibm
Ibm langflow Oss
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses
  • CWE-639

    Authorization Bypass Through User-Controlled Key

Sources

Status
PUBLISHED
Assigner
ibm
Published
Updated
May 1, 2026, 3:00 PM
Reserved
Apr 17, 2026, 5:59 PM
Status
Analyzed
Published
Apr 30, 2026, 10:16 PM
Modified
Oct 26, 2026, 9:10 PM