Auth bypass in IBM Langflow Oss

CVE-2026-18904

IBM Langflow OSS 1.0.0 through 1.11.1 could allow a remote attacker to obtain sensitive information and inject unauthorized messages due to a namespace collision between user identifiers.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (21.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-18904: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-18904?
CVE-2026-18904 is a high-severity vulnerability in IBM Langflow Oss, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.2/10. Published 2026-08-28.
How severe is CVE-2026-18904?
High severity. CVSS v3 base score is 8.2 out of 10.