CVE-2026-72840 OpenWrt LuCI luci-mod-system-mounts ACL Root RCE via Crontab Write
Authenticated users with mount permissions can write to root crontab, achieving root code execution via the default cron daemon.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-72840?
CVE-2026-72840 is a high-severity vulnerability in openwrt luci, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-266
Which versions are affected by CVE-2026-72840?
How do I fix CVE-2026-72840?
No fix has been published for CVE-2026-72840 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-72840 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72840 exists.
Sources
Also known as GHSA-6vfc-74mf-qrmj.