Buffer overflow in IBM I

CVE-2026-17220

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to cause a denial of service and modify authentication metadata due to a buffer overflow.

Vulnerability class: Buffer Overflow

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:N/I:L/A:H.

EPSS exploit prediction

EPSS: 0.006 (44.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 44.4% 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-2026-17220: held from 0.004 to 0.006.

EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002

Affected products

  • IBM I — versions 7.6, 7.5, 7.4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-17220?
CVE-2026-17220 is a high-severity vulnerability in IBM I, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.2/10. Published 2026-08-13.
How severe is CVE-2026-17220?
High severity. CVSS v3 base score is 8.2 out of 10.