RCE in IBM I
CVE-2026-8858
IBM WebSphere Application Server and IBM WebSphere Application Server Liberty are vulnerable to remote code execution and denial of service in the WebSphere Web Server Plug-in component. This vulnerability can be exploited when an attacker impersonates the application server and sends crafted responses to the plug-in.
Vulnerability class: RCE (Remote Code Execution)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (32.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 32.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- IBM I — versions 7.6.0, 7.5.0, 7.4.0
- IBM Websphere Application Server — versions 8.5, 9.0
Weakness classification (CWE)
References
- www.ibm.com/support/pages/node/7277344 (vendor-advisory, patch, Vendor Advisory)
- www.ibm.com/support/pages/node/7276560 (vendor-advisory, patch)
Frequently asked questions
- What is CVE-2026-8858?
- CVE-2026-8858 is a high-severity vulnerability in IBM I, classified under Code Injection. CVSS score: 7.5/10. Published 2026-06-22.
- How severe is CVE-2026-8858?
- High severity. CVSS v3 base score is 7.5 out of 10.