CVE-2026-13759

HIGH

IBM WebSphere eXtreme Scale is affected by Insecure Deserilization

Title source: cna
STIX 2.1

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory patch
https://www.ibm.com/support/pages/node/7278595

Scores

CVSS v3 7.5
EPSS 0.0030
EPSS Percentile 22.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-502
Status published
Products (2)
IBM/WebSphere Extreme Scale 8.6.1.0 - 8.6.1.6
ibm/websphere_extreme_scale 8.6.1.0 - 8.6.1.6
Published Jun 30, 2026
Tracked Since Jul 01, 2026