---
id: CVE-2026-55159
title: >-
  luci-app-adblock-fast a WebUI for fast, lightweight DNS-based ad-blocker for
  OpenWrt that works with dnsmasq, smartdns, or unbound
summary: >-
  luci-app-adblock-fast a WebUI for fast, lightweight DNS-based ad-blocker for
  OpenWrt that works with dnsmasq, smartdns, or unbound. Prior to 1.2.4-2, the
  luci.adblock-fast.setCronEntry RPC method accepts an entry argument containing
  carr…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-93
vendor: openwrt
product: luci-app-adblock-fast
affected:
  - luci-app-adblock-fast < 1.2.4-2
published: '2026-09-21'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:25:27.050'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55159'
references:
  - url: >-
      https://github.com/openwrt/luci/commit/9ccd99b5898457e5ef39dc21aea226d7fb6e5c7e
    label: security-advisories@github.com
  - url: >-
      https://github.com/openwrt/luci/commit/f67461fd0255bf992b2b559c22ec288067f2f9da
    label: security-advisories@github.com
  - url: 'https://github.com/openwrt/luci/pull/8705'
    label: security-advisories@github.com
  - url: 'https://github.com/openwrt/luci/security/advisories/GHSA-ggpf-xrph-wg5v'
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
epss: 0.00954
epssPercentile: 0.59692
ingestedAt: '2026-09-21T19:51:58.875Z'
---

## Overview

luci-app-adblock-fast a WebUI for fast, lightweight DNS-based ad-blocker for OpenWrt that works with dnsmasq, smartdns, or unbound. Prior to 1.2.4-2, the luci.adblock-fast.setCronEntry RPC method accepts an entry argument containing carriage-return or line-feed characters and serializes it into /etc/crontabs/root as though it were one logical line. An authenticated delegated user with the luci-app-adblock-fast write ACL can therefore create an additional physical root cron entry through applications/luci-app-adblock-fast/root/usr/share/rpcd/ucode/luci.adblock-fast, resulting in persistent command execution as UID 0 when cron runs. The issue is not demonstrated for unauthenticated callers or users without the component write ACL. This vulnerability is fixed in 1.2.4-2.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.