Authenticated code execution via unchecked MCP configuration
Published Oct 12, 2026 · Updated Oct 12, 2026
Code injection in 0xJacky Nginx UI before 2.4.1 allows remote authenticated users to execute code via MCP configuration creation. The nginx_config_add handler in mcp/config/config_add.go writes caller-supplied content and reloads nginx without calling ValidateConfigFile to reject restricted directives. Execution requires MCP authentication and available njs or Perl modules, including the official Docker deployment, and occurs in nginx workers.
Summary
What happened
Code injection in 0xJacky Nginx UI before 2.4.1 allows remote authenticated users to execute code via MCP configuration creation. The nginx_config_add handler in mcp/config/config_add.go writes caller-supplied content and reloads nginx without calling ValidateConfigFile to reject restricted directives. Execution requires MCP authentication and available njs or Perl modules, including the official Docker deployment, and occurs in nginx workers.
The record
- CVE
- CVE-2026-84317
- Published
- Oct 12, 2026
- Updated
- Oct 12, 2026
- Vendor
- 0xJacky
- Product
- Nginx UI
- Classifications
- CWE-20, T1059.007
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 12, 2026CVE publishedPublication date reported by the CVE source.
- Oct 12, 2026Record 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.
- Affected versionversion=< 2.4.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Public exploit references
- Upstream MCP configuration validation bypass proof of conceptproof of concept · demonstrated
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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