MAL-2026-10176: Malicious code in uncaxss (npm)
The uncaxss npm package versions 1.3.4 and 1.3.5 contain malicious code that executes during installation. The package runs an obfuscated script in its postinstall lifecycle hook which fetches remote code from an attacker-controlled server, decodes it, and executes it with full Node.js privileges. This behavior enables remote code execution on the machine installing the package. The malicious payload is conditionally activated based on an environment variable, allowing selective targeting. The package lacks legitimate documentation and the remote code source is opaque and mutable, indicating a deliberate backdoor.
AI Analysis
Technical Summary
The uncaxss npm package versions 1.3.4 and 1.3.5 include an obfuscated postinstall script that performs an HTTPS GET request to attacker-controlled URLs, retrieves base64-encoded JavaScript, and executes it dynamically using new Function with full Node.js capabilities. This results in remote code execution on the installer's system at install time. The payload activation is gated by the environment variable process.env.P set to 1, enabling selective execution, such as targeting CI environments. The obfuscation and lack of legitimate package documentation confirm malicious intent. No patch or remediation is currently documented.
Potential Impact
Installing affected versions of the uncaxss package results in remote code execution on the installing system with full Node.js privileges. This can lead to arbitrary code execution, potential system compromise, data theft, or further malware deployment. The selective activation mechanism allows attackers to evade detection by only triggering on specific environments.
Mitigation Recommendations
No official patch or remediation is currently available. Users should avoid installing versions 1.3.4 and 1.3.5 of the uncaxss package. Audit dependencies for this package and remove or replace it if found. Monitor for any updates from the package maintainer or npm advisories for remediation guidance.
MAL-2026-10176: Malicious code in uncaxss (npm)
Description
The uncaxss npm package versions 1.3.4 and 1.3.5 contain malicious code that executes during installation. The package runs an obfuscated script in its postinstall lifecycle hook which fetches remote code from an attacker-controlled server, decodes it, and executes it with full Node.js privileges. This behavior enables remote code execution on the machine installing the package. The malicious payload is conditionally activated based on an environment variable, allowing selective targeting. The package lacks legitimate documentation and the remote code source is opaque and mutable, indicating a deliberate backdoor.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The uncaxss npm package versions 1.3.4 and 1.3.5 include an obfuscated postinstall script that performs an HTTPS GET request to attacker-controlled URLs, retrieves base64-encoded JavaScript, and executes it dynamically using new Function with full Node.js capabilities. This results in remote code execution on the installer's system at install time. The payload activation is gated by the environment variable process.env.P set to 1, enabling selective execution, such as targeting CI environments. The obfuscation and lack of legitimate package documentation confirm malicious intent. No patch or remediation is currently documented.
Potential Impact
Installing affected versions of the uncaxss package results in remote code execution on the installing system with full Node.js privileges. This can lead to arbitrary code execution, potential system compromise, data theft, or further malware deployment. The selective activation mechanism allows attackers to evade detection by only triggering on specific environments.
Mitigation Recommendations
No official patch or remediation is currently available. Users should avoid installing versions 1.3.4 and 1.3.5 of the uncaxss package. Audit dependencies for this package and remove or replace it if found. Monitor for any updates from the package maintainer or npm advisories for remediation guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- MAL-2026-10176
- Osv Schema Version
- 1.7.4
- Aliases
- []
- Ecosystems
- ["npm"]
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a520eaf68715ace438f4c93
Added to database: 07/11/2026, 09:36:47 UTC
Last enriched: 07/11/2026, 09:47:41 UTC
Last updated: 07/12/2026, 03:33:20 UTC
Views: 3
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