CVE-2026-84317: high-severity vulnerability in 0xJacky nginx-ui
Nginx UI: MCP nginx_config_add skips config directive validation → authenticated nginx directive injection (RCE on the official image)
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.8epss 0.5%
Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, internal/config/validation.go (ValidateConfigFile) is a security control that blocks dangerous nginx directives — js_*, perl_*, load_module of the njs/perl modules, and user root. It is enforced on three of the four config-write paths: api/config/add.go, api/config/modify.go, and mcp/config/config_modify.go. The fourth path — the MCP tool nginx_config_add (mcp/config/config_add.go) — does NOT call it: it writes the caller-supplied content straight to disk and reloads nginx. An authenticated MCP caller (or an MCP agent induced via prompt injection) can therefore inject exactly the directives the control is meant to block, leading to nginx code execution on deployments where the njs/perl module is available (e.g. the official Docker image). This issue is fixed in version 2.4.1.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
0xJacky · nginx-uiRelated CVEs — 0xJacky nginx-ui
In the same product, most dangerous first.
CVE-2026-33032CRITICALNginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx TakeoverEPSS 35.3%CVE-2024-49368HIGHUnchecked logrotate settings lead to arbitrary command executionEPSS 27.7%CVE-2026-27944CRITICALNginx UI: Unauthenticated Backup Download with Encryption Key DisclosureEPSS 22.8%CVE-2024-22198HIGHAuthenticated (user role) arbitrary command execution by modifying `start_cmd` setting (GHSL-2023-268)EPSS 4.1%CVE-2024-22197HIGHAuthenticated (user role) remote command execution by modifying `nginx` settings (GHSL-2023-269)EPSS 1.5%CVE-2026-42221HIGHnginx-ui: Unauthenticated First-Run Installer Allows Remote Initial Admin ClaimEPSS 1.3%