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IApplication · Ibm

CVE-2026-8858

HIGH · 8.8 CVSS v3.1 Published 2026-06-22
Fix available
A fix is available. Upgrade to after 7.6 or later.
See remediation →
93/100
Remediation priority · Urgent
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Vulnerability in IBM WebSphere Web Server Plug-in allows remote code execution and denial of service via an impersonation attack where an attacker spoofing the application server sends crafted responses to the plug-in, compromising the integrity of the communication channel between the web server and application server.

MitigationImplement strong mutual authentication and message validation between the Web Server Plug-in and the application server to prevent impersonation attacks; apply IBM security patches when available.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
IApplication
Affected:>= 7.3, <= 7.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify WebSphere Web Server Plug-in is installed
    Locate the IBM WebSphere Web Server Plug-in installation directory and identify the plugin version using the product-specific version command or file metadata
    Affected if The plugin version falls within 7.3 to 7.6 inclusive
  2. Confirm the plugin is actively configured
    Check if the plugin is configured in the web server configuration to handle requests for IBM WebSphere applications
    Affected if The plugin is loaded and actively proxying requests to a WebSphere application server
  3. Identify the communication path between plugin and app server
    Examine the plugin configuration file (plugin-cfg.xml or equivalent) to determine which application server instances the plugin communicates with
    Affected if The plugin is configured to connect to any application server without strong mutual authentication enabled
  4. Check mutual authentication settings
    Inspect the plugin-to-app-server connection configuration for mutual TLS authentication and message validation settings
    Affected if Mutual authentication and message validation between the plugin and application server are disabled or set to weak defaults
  5. Assess network exposure of the plugin-to-app-server channel
    Determine if the network path between the web server hosting the plugin and the application server is accessible to potential attackers
    Affected if The communication channel is on a network segment accessible to untrusted parties, making impersonation feasible

You are affected if the IBM WebSphere Web Server Plug-in version is between 7.3 and 7.6 inclusive AND the plugin is actively configured to communicate with an application server without strong mutual authentication and message validation protecting that channel.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 7.6
Interim mitigation

Implement strong mutual authentication and message validation between the Web Server Plug-in and the application server to prevent impersonation attacks; apply IBM security patches when available.

Recommended fix Moderate confidence

WebSphere Application Server 9.0.5.x or later; WebSphere Application Server Liberty later fix pack

  1. 1. Identify the current WebSphere Application Server or Liberty installation version using the wsadmin script or administration console.
  2. 2. Review IBM's official security bulletin for CVE-2026-8858 at www.ibm.com for specific patch or fix pack information.
  3. 3. For WebSphere Application Server traditional: Upgrade to version 9.0.5.x or later, which contains the security fix for this vulnerability.
  4. 4. For WebSphere Application Server Liberty: Upgrade to a later fix pack that includes the resolution for this vulnerability.
  5. 5. Apply the fix through IBM Installation Manager or using the appropriate fix pack installation procedure.
  6. 6. Restart the WebSphere Application Server and Web Server Plug-in services after applying the fix.
  7. 7. Verify the fix by checking the installed version and confirming the vulnerability is resolved through IBM's recommended verification steps.
Caveat Upgrading from version 7.x to 9.0.x may require compatibility testing of applications; ensure applications are compatible with the newer Java version and API changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in I Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8858 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data