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CVE-2026-9170 IBM CVE debrief

IBM Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty versions 8.5 and 9.0 contain an improper input validation vulnerability (CWE-444) that may allow denial of service and potential remote code execution. The vulnerability affects IBM WebSphere Application Server and WebSphere Application Server Liberty. IBM has published a security bulletin with remediation guidance. The NVD entry shows this vulnerability is currently undergoing analysis with a CVSS 3.1 vector of AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N, indicating network attack vector, high attack complexity, no privileges required, no user interaction, changed scope, high confidentiality impact, low integrity impact, and no availability impact.

Vendor
IBM
Product
HTTP Server
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-26
Original CVE updated
2026-07-20
Advisory published
2026-05-26
Advisory updated
2026-07-20

Who should care

Organizations running IBM WebSphere Application Server or WebSphere Liberty with Web Server Plug-ins versions 8.5 or 9.0, particularly those with externally exposed web server front-ends. Security teams responsible for Java application server infrastructure and those managing hybrid cloud deployments using WebSphere Liberty.

Technical summary

The vulnerability stems from improper input validation (CWE-444) in IBM Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty. Affected versions include 8.5 and 9.0. The flaw may enable denial of service conditions and potentially allow remote code execution. Attack complexity is rated high per the CVSS vector, suggesting exploitation may require specific conditions or crafted requests. The changed scope (S:C) in the CVSS vector indicates the vulnerable component impacts resources beyond its security scope.

Defensive priority

HIGH

Recommended defensive actions

  • Review IBM security bulletin for affected product versions and available fixes
  • Apply vendor-provided patches or updates when available
  • Implement network segmentation to limit exposure of WebSphere management interfaces
  • Monitor for anomalous requests to Web Server Plug-in endpoints
  • Review access controls on WebSphere Application Server and Liberty deployments

Evidence notes

CVE published 2026-05-26T18:16:57.987Z; modified 2026-05-26T19:06:14.330Z. IBM PSIRT reference confirms vendor acknowledgment. NVD status: Undergoing Analysis. CVSS 3.1 vector provided in source metadata.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-9170 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-9170

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-9170 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-9170

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.