Vulnerability Description
IBM WebSphere Extreme Scale 8.6.1.0 through 8.6.1.6 ships three ObjectInputStream subclasses (WsObjectInputStream, ObjectStreamPool$ReusableInputStream, ObjectInputStreamResolver) that install no JEP-290 class filter; when Coherence is on the classpath, multiple RCE gadget chains including RemoteConstructor.readResolve and PriorityQueue/ExtractorComparator are confirmed working, allowing a post-login attacker who can write a session attribute or a LAN-adjacent attacker on the grid replication wire to execute arbitrary code on peer WAS JVMs
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Ibm | Websphere Extreme Scale | >= 8.6.1.0, <= 8.6.1.6 |
Related Weaknesses (CWE)
References
- https://www.ibm.com/support/pages/node/7278595Vendor Advisory
FAQ
What is CVE-2026-13759?
CVE-2026-13759 is a vulnerability with a CVSS score of 7.5 (HIGH). IBM WebSphere Extreme Scale 8.6.1.0 through 8.6.1.6 ships three ObjectInputStream subclasses (WsObjectInputStream, ObjectStreamPool$ReusableInputStream, ObjectInputStreamResolver) that install no JEP-...
How severe is CVE-2026-13759?
CVE-2026-13759 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-13759?
Check the references section above for vendor advisories and patch information. Affected products include: Ibm Websphere Extreme Scale.