CVE-2026-66256Network attack vector

Authenticated code execution via XStream deserialization

Published Aug 13, 2026 · Updated Aug 13, 2026

Deserialization in Apache Shindig all versions allows remote authenticated users to execute code through the OpenSocial REST API. Apache has not disclosed the specific request handler or XStream configuration that accepts the crafted payload and reconstructs an executable Java object graph. Exploitation requires authenticated access to the REST API and grants code execution in the server process of a retired, unsupported project.

CVSS severity7.2
High
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in Apache Shindig all versions allows remote authenticated users to execute code through the OpenSocial REST API. Apache has not disclosed the specific request handler or XStream configuration that accepts the crafted payload and reconstructs an executable Java object graph. Exploitation requires authenticated access to the REST API and grants code execution in the server process of a retired, unsupported project.

The record

CVE
CVE-2026-66256
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
The Apache Software Foundation
Product
Apache Shindig Social API
Classifications
CWE-502, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 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=0 <=*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Shindig Social APIversion=0 <=*
The Apache Software Foundation · Apache Shindig Commonversion=0 <=*

Published CVSS scores

7.2CISA-ADPCVSS:3.1/AV:N/AC:L/PR:H/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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
T1190Exploit Public-Facing Application

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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