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TI-2026-71318 Aliases CVE-2026-84318GHSA-9jww-cxg5-rj9m

Nginx UI MCP tool skips config validation, allowing authenticated RCE

Priority HIGH 73CWE-693Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-693.

Summary

Nginx UI from 2.0.0-rc.6 before 2.4.1 is affected. The MCP tool nginx_config_add writes nginx configuration files and reloads nginx without calling config.ValidateConfigFile, so dangerous directives such as perl, js_import, load_module and user root are not rejected (CWE-693). An authenticated attacker can write these directives, and on servers with the nginx Perl, njs or Lua module loaded this leads to remote code execution.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

Nginx UI is a web user interface for the Nginx web server. From 2.0.0-rc.6 until 2.4.1, the MCP tool nginx_config_add writes nginx configuration files to disk and triggers an nginx reload without calling config.ValidateConfigFile. The identical flow in the REST API (POST /api/configs) does call that function and correctly rejects dangerous directives. An authenticated attacker can exploit this gap to write config files containing any blocked directive (perl, js_import, load_module, user root, etc.), bypassing nginx-ui's entire security layer. On a server with the nginx Perl, njs, or Lua module loaded, this is post-authentication Remote Code Execution. This issue is fixed in version 2.4.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00816 57th percentileScored 2026-11-07
Fix Fixed nginx-ui (0xJacky): 2.4.1github.com/0xJacky/Nginx-UI (Go): 1.9.10-0.20260703131214-23d1934099b0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
0xJackynginx-ui2.0.0-rc.6 to before 2.4.12.4.1Patch availableCNA
—github.com/0xJacky/Nginx-UI (Go)1.9.10-0.20250506154222-1330888280a2 to before 1.9.10-0.20260703131214-23d1934099b01.9.10-0.20260703131214-23d1934099b0Patch availableGHSA-9jww-cxg5-rj9m
  • nginx-ui Vendor0xJacky Affected 2.0.0-rc.6 to before 2.4.1 Fixed in 2.4.1 Patch available CNA
  • github.com/0xJacky/Nginx-UI (Go) Vendor— Affected 1.9.10-0.20250506154222-1330888280a2 to before 1.9.10-0.20260703131214-23d1934099b0 Fixed in 1.9.10-0.20260703131214-23d1934099b0 Patch available GHSA-9jww-cxg5-rj9m

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:nginxui:nginx_ui:*:*:*:*:*:*:*:*——0xJacky
  • cpe:2.3:a:nginxui:nginx_ui:*:*:*:*:*:*:*:* Versions — — ·0xJacky

Remediation

Upgrade nginx-ui to version 2.4.1. The Go module github.com/0xJacky/Nginx-UI is fixed in 1.9.10-0.20260703131214-23d1934099b0, so update it to that version or later.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA nginx-ui (0xJacky) Fixed in 2.4.1
  • Fix · GHSA-9jww-cxg5-rj9m github.com/0xJacky/Nginx-UI (Go) Fixed in 1.9.10-0.20260703131214-23d1934099b0 Advisory →

Timeline

  1. 2026-10-12 Threatist record created from CVE-2026-84318
  2. 2026-10-13 CISA SSVC decision points changed
  3. 2026-10-13 Priority changed: MEDIUM → HIGH
  4. 2026-10-16 Alias added: GHSA-9jww-cxg5-rj9m
  5. 2026-10-16 Fix available: Go/github.com/0xJacky/[email protected] · GHSA-9jww-cxg5-rj9m
  6. 2026-10-16 CVSS score added · GHSA-9jww-cxg5-rj9m
  7. 2026-10-16 Weakness changed · GHSA-9jww-cxg5-rj9m
  8. 2026-10-16 5 new references · GHSA-9jww-cxg5-rj9m
  9. 2026-10-25 EPSS moved to the 50th–90th percentile

References

Advisory 1

Other 4

  • TI-2026-25478 Nginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx Takeover CVSS 3.1CRITICAL 9.8
  • TI-2026-25472 nginx-ui Backup Restore Allows Tampering with Encrypted Backups CVSS 4.0CRITICAL 9.4
  • TI-2026-22288 Nginx UI: Unauthenticated Backup Download with Encryption Key Disclosure CVSS 3.1CRITICAL 9.8
  • TI-2024-15821 Nginx-UI arbitrary file write through the Import Certificate feature CVSS 3.1CRITICAL 9.8
  • TI-2026-70057 Code injection in Nginx UI backup restore allows code execution CVSS 4.0CRITICAL 9.4
  • TI-2026-32056 Nginx UI: Server-Side Request Forgery (SSRF) via Cluster Proxy Middleware Allows Access to Internal Services CVSS 3.1CRITICAL 9.9
See all 43 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences