Auth bypass in IBM I

CVE-2026-18509

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local authenticated attacker to gain privilege escalation via the Navigator for i debugger. This could allow the attacker to access or manipulate sensitive data on the system, or create new profiles with elevated privileges on the IBM i system.

Published · last modified .

CVSS v3 metric

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

EPSS exploit prediction

EPSS: 0.002 (12.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 12.7% 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-2026-18509: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.001

Affected products

  • IBM I — versions 7.6, 7.5, 7.4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-18509?
CVE-2026-18509 is a high-severity vulnerability in IBM I, classified under Improper Authorization. CVSS score: 8.2/10. Published 2026-08-13.
How severe is CVE-2026-18509?
High severity. CVSS v3 base score is 8.2 out of 10.