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VulnerabilityPublished Updated

CVE-2026-55159: openwrt luci-app-adblock-fast · CRLF Injection

Affects openwrt luci-app-adblock-fastSource CVE Database V5

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Not known to be exploited · CVSS 8.8 High : upgrade to 1.2.4-2 soon.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.2.4-2
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 21 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Upgrade luci-app-adblock-fast and openwrt/luci-app-adblock-fast to 1.2.4-2.

Affected software

ProductAffectedFixed in
openwrtluci-app-adblock-fastAffected
  • <1.2.4-2
Fixed in
  • 1.2.4-2
GitHubopenwrt/luci-app-adblock-fastpkg:github/openwrt/luci-app-adblock-fastOther threatsAffected
  • <1.2.4-2
Fixed in
  • 1.2.4-2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade luci-app-adblock-fast to version 1.2.4-2 or later, where this vulnerability is fixed. Until the upgrade, restrict write ACL permissions to trusted users only. No other mitigations are specified by the vendor.

Description

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.

References

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