CVE-2007-3537: IBM OS 400

High severity, CVSS 7.8. EPSS: 1.5% chance of exploitation in the next 30 days.

IBM OS/400 (aka i5/OS) V4R2M0 through V5R3M0 on iSeries machines sends responses to TCP SYN-FIN packets, which allows remote attackers to obtain system information and possibly bypass firewall rules.

Affected products

• IBM OS 400: version r520 only; version v4r2m0 only; version v4r3 only; version v4r4 only; version v4r5 only; version v5r1 only; …

Published 2007-07-03. Last modified 2026-06-16.