CVE-2023-39106Public exploitNetwork attack vector

Remote code execution via unrestricted YAML type instantiation

Published Aug 21, 2023 · Updated Oct 7, 2024

Unsafe deserialization in Nacos Spring Project 1.1.1 and earlier allows remote authenticated users to execute arbitrary code via YAML. nacos-spring-context passes NacosPropertySource YAML to SnakeYAML Constructor(), which instantiates attacker-selected Java types without restrictions. Access to modify a referenced YAML configuration on the Nacos server is required, and a malicious type can load attacker-controlled code in the consuming Spring application.

CVSS severity8.8
High
EPSS probability1.29%
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 Nacos Spring Project 1.1.1 and earlier allows remote authenticated users to execute arbitrary code via YAML. nacos-spring-context passes NacosPropertySource YAML to SnakeYAML Constructor(), which instantiates attacker-selected Java types without restrictions. Access to modify a referenced YAML configuration on the Nacos server is required, and a malicious type can load attacker-controlled code in the consuming Spring application.

The record

CVE
CVE-2023-39106
Published
Aug 21, 2023
Updated
Oct 7, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 7, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8GitHubCVSS:3.1/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
T1203Exploitation for Client Execution

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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