Review reviewCritical

CVE-2026-13773

IBM WebSphere Extreme Scale, websphere extreme scale

IBM WebSphere Extreme Scale 8.6.1.0 through 8.6.1.6 Approximately 50 generated CORBA stub classes in WebSphere eXtreme Scale's ogclient.jar call ORB.string_to_object() on an attacker-controlled IOR string during Java deserialization, turning any unfiltered ObjectInputStream sink in WAS into outbound IIOP SSRF to an attacker-chosen host; when chained with the IBM ORB's getUserException class-instantiation flaw (WAS-26), this SSRF escalates to remote code execution on the calling JVM.

CVSS: 10
EPSS: 3.42%
CISA KEV: Not listed
Published: 2026.07.01

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability3.42%

Technical severityCVSS 10

Vulnerability overview

Affected product and versions

Product: IBM WebSphere Extreme Scale, websphere extreme scale
Affected versions: 8.6.1.0, >= 8.6.1.0 <= 8.6.1.6
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that IBM WebSphere Extreme Scale, websphere extreme scale and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CWE: CWE-918