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CVE-2026-84317

HIGH 8.8

Published 2026-10-12 · Last modified 2026-10-13

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.

ELEVATED IMPACT

Severe if exploited (CVSS 8.8), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 41st percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

8.8CVSS 3.1 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires a low-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors 0xjacky

Products Nginx Ui

Weakness (CWE)

  • CWE-20: : Improper Input Validation
  • CWE-693: : Protection Mechanism Failure

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References and research data (JSON)

Packages and version ranges

Each advisory describes its own package and affected ranges. A boundary applies to that range; it is not a universal upgrade recommendation.

  • github.com/0xJacky/Nginx-UI Go

    pkg:golang/github.com/0xJacky/Nginx-UI

    SEMVER range
    • All earlier versions (introduced 0)
    • Fixed boundary (excluded): 1.9.10-0.20260703131214-23d1934099b0
    Additional upstream package constraints
    {
  "database": {
    "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-76pm-mq2q-9gcr/GHSA-76pm-mq2q-9gcr.json"
  }
}
    GitHub Advisory Database · GHSA-76pm-mq2q-9gcr · Updated 2026-10-19T21:41:06.485505015Z
  • github.com/0xJacky/Nginx-UI Go

    pkg:golang/github.com/0xJacky/Nginx-UI

    SEMVER range
    • All earlier versions (introduced 0)
    • Fixed boundary (excluded): 1.9.10-0.20260703131214-23d1934099b0
    Additional upstream package constraints
    {
  "ecosystem": {},
  "database": {
    "source": "https://vuln.go.dev/ID/GO-2026-6779.json"
  }
}
    Go Vulnerability Database · GO-2026-6779 · Updated 2026-10-19T21:31:53.419235882Z

All CVSS metrics

  • HIGH 8.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • HIGH 8.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Exploit-tagged references (not proof of a PoC)

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS