CVE-2026-103499: IBM WebSphere Application Server denial of service via resource consumption

CVE-2026-103499 · Severity: high · CVSS 7.5 · Published 2026-10-13

IBM WebSphere Application Server and Liberty are Java application servers used to host business-critical web applications. A remote attacker can send specially crafted requests that cause the server to consume excessive memory or CPU resources, leading to service unavailability and business disruption.

Technologies: IBM WebSphere Application Server, IBM WebSphere Application Server Liberty. Vendors: IBM.

Quick answers

Is CVE-2026-103499 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-103499 being exploited in the wild.
How severe is CVE-2026-103499?
High severity, with a CVSS score of 7.5, published 13 October 2026.
Which products and versions are affected?
IBM WebSphere Application Server 8.5.0.0 through 8.5.5.31, 9.0.0.0 through 9.0.5.29; IBM WebSphere Application Server Liberty 17.0.0.3 through 26.0.0.10.
Is there a fix for CVE-2026-103499?
Yes: fixed in WebSphere Application Server - Liberty 26.0.0.11 or later; WebSphere Application Server 8.5.5.32 or later, 9.0.5.30 or later. Interim fixes APAR DT502944 (Liberty) and DT502943 (traditional WAS) also available.. Until then: Interim fixes resolving APAR DT502944 (Liberty) or DT502943 (traditional WAS) are available for immediate deployment prior to applying full fix packs. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-103499 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-103499?
Check whether you run IBM WebSphere Application Server or IBM WebSphere Application Server Liberty 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.

How to fix

  • Fixed in: WebSphere Application Server - Liberty 26.0.0.11 or later; WebSphere Application Server 8.5.5.32 or later, 9.0.5.30 or later. Interim fixes APAR DT502944 (Liberty) and DT502943 (traditional WAS) also available.

Interim fixes resolving APAR DT502944 (Liberty) or DT502943 (traditional WAS) are available for immediate deployment prior to applying full fix packs.

Technical details

An uncontrolled resource consumption vulnerability (CWE-400) in the servlet handling features allows a remote unauthenticated attacker to trigger denial of service. The vulnerability affects Liberty versions 17.0.0.3 through 26.0.0.10 and traditional WebSphere Application Server versions 8.5 and 9.0 when servlet features (3.0–6.1) are enabled. Exploitation requires only network access with no authentication or user interaction.

Affected products

  • IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.10
  • IBM WebSphere Application Server 8.5.0.0 through 8.5.5.31, 9.0.0.0 through 9.0.5.29

Timeline

  • 2026-10-13: disclosed

References

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