CVE-2026-8858

WebSphere Application Server Remote Code Execution

7.5 High

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.

Attack profile

How easy it is to exploit

Attack vector: Adjacent network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.41%Up 0.2 points since Jun 23, 2026

What each source reports

CVE List Score used 7.5

WebSphere Application Server Remote Code Execution

Record: CVE-2026-8858
CVSS 3.1: 7.5 HighCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-94
Updated: 2026-11-02

EUVDEUVD-2026-38284 7.5

Record: EUVD-2026-38284
CVSS 3.1: 7.5 HighCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-mfq9-47xf-5654 7.5

IBM i 7.6, 7.5, 7.4, and 7.3, IBM WebSphere Application Server and IBM WebSphere Application...

IBM i 7.6, 7.5, 7.4, and 7.3, 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.

Record: GHSA-mfq9-47xf-5654
CVSS 3.1: 7.5 HighCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-94
Updated: 2026-11-02

NVD 7.5

Record: CVE-2026-8858
CVSS 3.1: 7.5 HighCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1: 8.8 HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-94
Updated: 2026-11-02

Affected products

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-8858 is a high vulnerability (CVSS 7.5) in Ibm I, published June 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 35th percentile. No source names a fixed version.