CVE-2026-72840: Incorrect Privilege Assignment in openwrt luci
CVE-2026-72840 is a high-severity vulnerability in OpenWrt LuCI where an overly permissive ACL in luci-mod-system-mounts allows authenticated users with mount-configuration privileges to write arbitrary cron jobs to /etc/crontabs/root. These cron jobs are executed by the root-owned busybox crond daemon within one minute, enabling privilege escalation.
AI Analysis
Technical Summary
OpenWrt LuCI's luci-mod-system-mounts component defines an overly permissive access control list (ACL) that grants write access to the root user's crontab file (/etc/crontabs/root) to users who should only have mount configuration permissions. Authenticated users in the mount-configuration ACL group can exploit this by appending arbitrary cron entries via the ubus file.write interface. The default busybox crond daemon runs these cron jobs as root within one minute, resulting in a privilege escalation vulnerability.
Potential Impact
An authenticated user with limited mount-configuration privileges can escalate their privileges to root by injecting arbitrary cron jobs that the root-owned crond daemon executes. This can lead to full system compromise.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to the mount-configuration ACL group to trusted users only and monitor for suspicious cron file modifications if possible.
CVE-2026-72840: Incorrect Privilege Assignment in openwrt luci
Description
CVE-2026-72840 is a high-severity vulnerability in OpenWrt LuCI where an overly permissive ACL in luci-mod-system-mounts allows authenticated users with mount-configuration privileges to write arbitrary cron jobs to /etc/crontabs/root. These cron jobs are executed by the root-owned busybox crond daemon within one minute, enabling privilege escalation.
CVSS v4.0
Score 8.7high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
OpenWrt LuCI's luci-mod-system-mounts component defines an overly permissive access control list (ACL) that grants write access to the root user's crontab file (/etc/crontabs/root) to users who should only have mount configuration permissions. Authenticated users in the mount-configuration ACL group can exploit this by appending arbitrary cron entries via the ubus file.write interface. The default busybox crond daemon runs these cron jobs as root within one minute, resulting in a privilege escalation vulnerability.
Potential Impact
An authenticated user with limited mount-configuration privileges can escalate their privileges to root by injecting arbitrary cron jobs that the root-owned crond daemon executes. This can lead to full system compromise.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to the mount-configuration ACL group to trusted users only and monitor for suspicious cron file modifications if possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-10T15:13:41.486Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a7e412ebf8831d539e05145
Added to database: 08/13/2026, 22:11:58 UTC
Last enriched: 08/13/2026, 22:27:15 UTC
Last updated: 08/13/2026, 22:27:15 UTC
Views: 3
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