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CVE-2026-72840— OpenWrt LuCI luci-mod-system-mounts ACL Root RCE via Crontab Write

Quick assessment

Affected
openwrt luci
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

OpenWRT LuCI是OpenWRT社区开源的一个网页管理界面。 OpenWRT LuCI存在权限许可和访问控制问题漏洞，该漏洞源于luci-mod-system-mounts中过于宽松的ACL定义，将/etc/crontabs/root的写权限授予仅用于挂载配置的用户，可能导致经身份验证的用户通过ubus file.write追加任意cron条目，并以root权限执行。

CVSS 8.8 · High EPSS 0.38% · P32

Affected Version Matrix 1

VendorProduct Version RangeStatus
openwrt luci any affected
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I. Basic Information for CVE-2026-72840

Vulnerability Information
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Vulnerability Title
OpenWrt LuCI luci-mod-system-mounts ACL Root RCE via Crontab Write
Source: CVE Program / CVE List V5
Vulnerability Description
OpenWrt LuCI contains an overly permissive ACL definition in luci-mod-system-mounts that grants write access to /etc/crontabs/root to users intended only for mount configuration. Authenticated users with only the mount-configuration ACL group can append arbitrary cron entries via ubus file.write, which the default busybox crond daemon executes as root within one minute.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
特权授予不正确
Source: CVE Program / CVE List V5
Vulnerability Title
OpenWRT LuCI 权限许可和访问控制问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
OpenWRT LuCI是OpenWRT社区开源的一个网页管理界面。 OpenWRT LuCI存在权限许可和访问控制问题漏洞，该漏洞源于luci-mod-system-mounts中过于宽松的ACL定义，将/etc/crontabs/root的写权限授予仅用于挂载配置的用户，可能导致经身份验证的用户通过ubus file.write追加任意cron条目，并以root权限执行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
openwrt luci - -

II. Public POCs for CVE-2026-72840

# POC Description Source Link Shenlong Link
AI-Generated POC Verified env Premium
Reproduced successfully in a real sandbox · Below is the actual recording of building the environment and exploiting the vulnerability.
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Qwen3.6-35B-A3B · 9664 chars
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III. Intelligence Information for CVE-2026-72840

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Vendor Advisories for CVE-2026-72840 (2)

Same Patch Batch · openwrt · 2026-08-13 · 3 CVEs total

CVE-2026-72842 9.9 CRITICAL OpenWrt luci-app-lxc ACL Inconsistency Authentication Bypass
CVE-2026-72841 9.9 CRITICAL luci-app-openvpn Path Traversal RCE via instance_name2

IV. Related Vulnerabilities

Same product: luci
Same vendor: openwrt
Same weakness: CWE-266

V. Comments for CVE-2026-72840

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