8.8

CVE-2026-13759: ibm websphere_extreme_scale Deserialization of Untrusted Data

CVSS: 8.8v3.1HighAnalyzed
Published 30-06-2026Last modified 03-07-2026
Open JSON

Vulnerability summary

CVE-2026-13759 is a high (CVSS 8.8) Deserialization of Untrusted Data vulnerability in ibm websphere_extreme_scale. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 44.7% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (NVD)
EPSS score
0.55%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 30-06-2026
    PublishedVulnerability first disclosed.
  2. 03-07-2026
    Last modifiedVulnerability information updated.

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 metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.55%

Chance of exploitation in the next 30 days

Percentile

45%

Versus all other CVEs

30-day change

0.00 pp

From 0.55% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.55%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ibm1 product

1 vendor · 1 product

References

1 links