Buffer overflow in IBM I

CVE-2026-18846

IBM i 7.6, 7.5, 7.4, and 7.3 s vulnerable to a buffer overflow from improperly validating client data. By sending malformed requests to one of the host servers, a remote attacker could leverage this vulnerability to cause a denial-of-server (DoS) for that server.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (43.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.5% 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-2026-18846: held from 0.004 to 0.005.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.002

Affected products

  • IBM I — versions 7.6, 7.5, 7.4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-18846?
CVE-2026-18846 is a high-severity vulnerability in IBM I, classified under Out-of-bounds Write. CVSS score: 7.5/10. Published 2026-08-13.
How severe is CVE-2026-18846?
High severity. CVSS v3 base score is 7.5 out of 10.