CVE-2021-37632Network attack vector

Remote code execution via unsafe packet deserialization

Published Aug 5, 2021 · Updated Aug 4, 2024

Unsafe deserialization in SuperMartijn642's Config Lib allows remote attackers to execute code through crafted config-sync packets. ConfigSyncPacket passes unvalidated enum data to ObjectInputStream.readObject, which instantiates attacker-chosen classes. A malicious server can target connected clients, and a malicious client can theoretically target a server when a suitable class is available.

CVSS severity8.1
High
EPSS probability1.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in SuperMartijn642's Config Lib allows remote attackers to execute code through crafted config-sync packets. ConfigSyncPacket passes unvalidated enum data to ObjectInputStream.readObject, which instantiates attacker-chosen classes. A malicious server can target connected clients, and a malicious client can theoretically target a server when a suitable class is available.

The record

CVE
CVE-2021-37632
Published
Aug 5, 2021
Updated
Aug 4, 2024
Vendor
SuperMartijn642
Product
SuperMartijn642's Config Lib
Classifications
CWE-502, T1203, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 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=>= 1.0.4, < 1.0.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SuperMartijn642 · SuperMartijn642's Config Libversion=>= 1.0.4, < 1.0.8

Published CVSS scores

8.1GitHubCVSS:3.1/AV:N/AC:H/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1203Exploitation for Client Execution
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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