CVE-2026-13759Network attack vector

Code execution via unfiltered Java deserialization

Published Jun 30, 2026 · Updated Jun 30, 2026

Insecure deserialization in IBM WebSphere eXtreme Scale 8.6.1.0 through 8.6.1.6 allows remote authenticated users to execute code. WsObjectInputStream, ObjectStreamPool$ReusableInputStream, and ObjectInputStreamResolver deserialize untrusted objects without a JEP 290 class filter, permitting Coherence gadget chains. Exploitation requires either post-login control of a session attribute or LAN access to the grid replication wire; code runs in a peer WAS JVM.

CVSS severity7.5
High
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure deserialization in IBM WebSphere eXtreme Scale 8.6.1.0 through 8.6.1.6 allows remote authenticated users to execute code. WsObjectInputStream, ObjectStreamPool$ReusableInputStream, and ObjectInputStreamResolver deserialize untrusted objects without a JEP 290 class filter, permitting Coherence gadget chains. Exploitation requires either post-login control of a session attribute or LAN access to the grid replication wire; code runs in a peer WAS JVM.

The record

CVE
CVE-2026-13759
Published
Jun 30, 2026
Updated
Jun 30, 2026
Vendor
OpenBMC Project
Product
IBM WebSphere eXtreme Scale
Classifications
CWE-502, T1210
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.6.1.0 <=8.6.1.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenBMC Project · IBM WebSphere eXtreme Scaleversion=8.6.1.0 <=8.6.1.6

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.5IBM CorporationCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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