Quick answers
- Is CVE-2026-18251 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-18251 being exploited in the wild.
- How severe is CVE-2026-18251?
- Medium severity, with a CVSS score of 4.3, published 14 September 2026.
- Which products and versions are affected?
- IBM I 7.3, 7.4, 7.5, 7.6.
- Is there a fix for CVE-2026-18251?
- A patch was published on 2026-09-14: PTF patches available for all affected versions Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-18251 attacked?
- It is attacked over the network, in an operating system.
- Am I affected by CVE-2026-18251?
- Check whether you run IBM I at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is a missing origin validation flaw (CWE-1385) in the WebSocket implementation of IBM i versions 7.3 through 7.6. The affected component improperly validates the origin header during WebSocket handshake, allowing a remote attacker without authentication to establish unauthorized WebSocket connections and access sensitive information. The attack requires user interaction (UI:R) and is network-accessible (AV:N). IBM has released PTF patches (SJ11196, SJ11197, SJ11200, SJ11187 for 7.6, 7.5, 7.4, 7.3 respectively under Option 3, and SJ11377, SJ11376, SJ11375, SJ11374 under Option 34) to remediate this issue.
Affected products
- IBM i 7.3, 7.4, 7.5, 7.6
Timeline
- 2026-09-14: disclosed
- 2026-09-14: patched: PTF patches available for all affected versions