CVE-2026-55388: CWE-94: Improper Control of Generation of Code ('Code Injection') in piscinajs piscina
piscina is a node.js worker pool implementation. Prior to 6.0.0-rc.2, 5.2.0, and 4.9.3, piscina's constructor and run() paths read the filename option via plain member access. Both reads fall through the prototype chain when the caller's options object doesn't have filename as an own property. When Object.prototype.filename is polluted upstream the inherited value flows to worker_threads.Worker import and the attacker's .mjs runs in the worker. This vulnerability is fixed in 6.0.0-rc.2, 5.2.0, and 4.9.3.
AI Analysis
Technical Summary
The vulnerability in piscina arises because its constructor and run() methods access the filename option using plain member access, which falls through the prototype chain if the caller's options object lacks an own filename property. If an attacker pollutes Object.prototype.filename upstream, the inherited malicious value is passed to worker_threads.Worker import, resulting in arbitrary code execution in the worker context. This issue is addressed in piscina versions 6.0.0-rc.2, 5.2.0, and 4.9.3.
Potential Impact
Successful exploitation allows an unauthenticated attacker to execute arbitrary code within a worker thread, potentially leading to full compromise of the application using piscina. The CVSS 3.1 score of 8.1 reflects high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix is available in piscina versions 4.9.3, 5.2.0, and 6.0.0-rc.2. Users should upgrade to at least version 5.2.0 or 4.9.3 to remediate this vulnerability. Patch status is confirmed by the version information in the advisory. No other vendor advisory content is provided.
CVE-2026-55388: CWE-94: Improper Control of Generation of Code ('Code Injection') in piscinajs piscina
Description
piscina is a node.js worker pool implementation. Prior to 6.0.0-rc.2, 5.2.0, and 4.9.3, piscina's constructor and run() paths read the filename option via plain member access. Both reads fall through the prototype chain when the caller's options object doesn't have filename as an own property. When Object.prototype.filename is polluted upstream the inherited value flows to worker_threads.Worker import and the attacker's .mjs runs in the worker. This vulnerability is fixed in 6.0.0-rc.2, 5.2.0, and 4.9.3.
CVSS v3.1
Score 8.1high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in piscina arises because its constructor and run() methods access the filename option using plain member access, which falls through the prototype chain if the caller's options object lacks an own filename property. If an attacker pollutes Object.prototype.filename upstream, the inherited malicious value is passed to worker_threads.Worker import, resulting in arbitrary code execution in the worker context. This issue is addressed in piscina versions 6.0.0-rc.2, 5.2.0, and 4.9.3.
Potential Impact
Successful exploitation allows an unauthenticated attacker to execute arbitrary code within a worker thread, potentially leading to full compromise of the application using piscina. The CVSS 3.1 score of 8.1 reflects high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix is available in piscina versions 4.9.3, 5.2.0, and 6.0.0-rc.2. Users should upgrade to at least version 5.2.0 or 4.9.3 to remediate this vulnerability. Patch status is confirmed by the version information in the advisory. No other vendor advisory content is provided.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-16T18:57:40.183Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a39735deed863c81e3962f6
Added to database: 06/22/2026, 17:39:41 UTC
Last enriched: 06/29/2026, 21:52:28 UTC
Last updated: 08/06/2026, 00:41:14 UTC
Views: 56
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