What is CVE-2026-18891?

CVE-2026-18891 is a high-severity vulnerability in IBM Langflow Oss, classified under Improper Authentication. CVSS score: 8.2/10. Published 2026-08-28.

How severe is CVE-2026-18891?

High severity. CVSS v3 base score is 8.2 out of 10.

Auth bypass in IBM Langflow Oss

CVE-2026-18891

IBM Langflow OSS 1.0.0 through 1.11.1 could allow a remote attacker to execute arbitrary flows and access sensitive information due to improper authentication.

Vulnerability class: Broken Authentication

Published 2026-08-28 · last modified 2026-08-31.

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 (23.0th percentile), scored 2026-10-13.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

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

Affected products

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

www.ibm.com/support/pages/node/7284579 (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-18891?: CVE-2026-18891 is a high-severity vulnerability in IBM Langflow Oss, classified under Improper Authentication. CVSS score: 8.2/10. Published 2026-08-28.
How severe is CVE-2026-18891?: High severity. CVSS v3 base score is 8.2 out of 10.