CVE-2021-34992Public exploitNetwork attack vector

Authenticated code execution via unrestricted JSON type binding

Published Nov 15, 2021 · Updated Aug 4, 2024

Deserialization in Composite.dll in Orckestra C1 CMS 6.10 allows remote authenticated users to execute code through crafted JSON. CompositeJsonSerializer uses TypeNameHandling.Auto, while CompositeSerializationBinder passes unapproved assembly and type names to the default binder. Any C1 Console account can reach the flaw, and successful exploitation runs code under the website service account.

CVSS severity8.8
High
EPSS probability4.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in Composite.dll in Orckestra C1 CMS 6.10 allows remote authenticated users to execute code through crafted JSON. CompositeJsonSerializer uses TypeNameHandling.Auto, while CompositeSerializationBinder passes unapproved assembly and type names to the default binder. Any C1 Console account can reach the flaw, and successful exploitation runs code under the website service account.

The record

CVE
CVE-2021-34992
Published
Nov 15, 2021
Updated
Aug 4, 2024
Vendor
Orckestra
Product
C1 CMS Foundation
Classifications
CWE-502, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=6.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Orckestra · C1 CMS Foundationversion=6.10

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8Zero Day InitiativeCVSS:3.0/AV:N/AC:L/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.

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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 exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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