CVE-2026-9002
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk19th percentile - higher than 19% of all known CVEs
Summary
IBM WebSphere Extreme Scale versions 8.6.1.0 through 8.6.1.6 contain a denial-of-service vulnerability due to improper validation in the XDF decoder. The application processes deeply nested Protocol Buffers messages and attacker-controlled length prefixes without sufficient bounds checking, which may lead to a StackOverflowError or OutOfMemoryError.
Risk Assessment
An adjacent attacker on the same network can crash the WebSphere Application Server JVM, causing service disruption and potential loss of application availability.
Recommendation
Immediately upgrade IBM WebSphere Extreme Scale to version 8.6.1.7 or later, which includes a fix for this vulnerability.
Other vulnerabilities in IBM WebSphere Extreme Scale
See all- CVE-2026-13773Medium
IBM WebSphere Extreme Scale 8.6.1.0 through 8.6.1.6 contains approximately 50 generated CORBA stub classes in ogclient.jar that call ORB.string_to_object() on an attacker-controlled IOR string during Java deserialization. This turns any unfiltered ObjectInputStream sink in WAS into outbound IIOP SSRF to an attacker-chosen host.
- CVE-2026-13772High
IBM WebSphere Extreme Scale 8.6.1.0 through 8.6.1.6 contains a vulnerability in the Object Query Language engine that resolves attacker-supplied class names via Class.forName() and invokes their constructors without an allow-list at three distinct sinks (SELECT NEW, enum literals, and reflection-based comparators). An authenticated remote attacker who can influence an application-built OQL query string can execute arbitrary constructors on the WAS JVM, and a SELECT DISTINCT variant using planted grid values triggers the same gadget post-deserialization in a manner that bypasses JEP-290 serialization filters across grid node boundaries.
- CVE-2026-13759High
IBM WebSphere Extreme Scale 8.6.1.0 through 8.6.1.6 ships three ObjectInputStream subclasses (WsObjectInputStream, ObjectStreamPool$ReusableInputStream, ObjectInputStreamResolver) that install no JEP-290 class filter; when Coherence is on the classpath, multiple RCE gadget chains including RemoteConstructor.readResolve and PriorityQueue/ExtractorComparator are confirmed working, allowing a post-login attacker who can write a session attribute or a LAN-adjacent attacker on the grid replication wire to execute arbitrary code on peer WAS JVMs.
Original NVD description (English source)
IBM WebSphere Extreme Scale 8.6.1.0 through 8.6.1.6 could allow an adjacent attacker to cause a denial of service due to improper validation in the XDF decoder. The application processes deeply nested Protocol Buffers messages and attacker-controlled length prefixes without sufficient bounds checking, which may allow an attacker on the same network to trigger a StackOverflowError or OutOfMemoryError, resulting in a crash of the WebSphere Application Server JVM.