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.

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.

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.