What is CVE-2026-72840?

CVE-2026-72840 is a high-severity vulnerability in Openwrt Luci, classified under Incorrect Privilege Assignment. CVSS score: 8.8/10. Published 2026-08-13.

How severe is CVE-2026-72840?

High severity. CVSS v3 base score is 8.8 out of 10.

Privilege escalation in Openwrt Luci

CVE-2026-72840

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.

Published 2026-08-13 · last modified 2026-09-09.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (35.9th percentile), scored 2026-09-28.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 35.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Openwrt Luci

Weakness classification (CWE)

CWE-266 — Incorrect Privilege Assignment

References

github.com/openwrt/luci/security/advisories/GHSA-v5f9-62c7-cw29 (vendor-advisory)
www.vulncheck.com/advisories/openwrt-luci-luci-mod-system-mounts-acl-root-rce-v… (third-party-advisory)

Frequently asked questions

What is CVE-2026-72840?: CVE-2026-72840 is a high-severity vulnerability in Openwrt Luci, classified under Incorrect Privilege Assignment. CVSS score: 8.8/10. Published 2026-08-13.
How severe is CVE-2026-72840?: High severity. CVSS v3 base score is 8.8 out of 10.