CVE-2026-35521: FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface

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HIGH 8.8UPGRADE

CVE-2026-35521 is a high-severity flaw (CVSS 8.8) affecting ftldns. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface. From 6.0 to before 6.6, the Pi-hole FTL engine contains a Remote Code Execution (RCE) vulnerability in the DHCP hosts configuration parameter (dhcp.hosts). This vulnerability allows an authenticated attacker to inject arbitrary dnsmasq configuration directives through newline characters, ultimately achieving command execution on the underlyi

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-78, CWE-93
Published	2026-04-07
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: pi-hole

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-07 16:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

pi-hole ftldns UPGRADE

Affected: >= 6.0 and <= 6.5

Fixed in: newer than 6.5

Safe to downgrade to: a release before 6.0

1. Check installed version

apt-cache policy ftldns || rpm -q ftldns || ftldns --version

2. UPGRADE to newer than 6.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ftldns

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ftldns

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 6.0 (Debian / Ubuntu)

apt-cache madison ftldns sudo apt install ftldns=<VERSION_BEFORE_6.0> sudo apt-mark hold ftldns

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ftldns sudo dnf downgrade ftldns-<VERSION_BEFORE_6.0> sudo dnf versionlock add ftldns

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-35521?

ftldns: upgrade to newer than 6.5. Exact commands for each OS are on this page.

Is CVE-2026-35521 being exploited?

CVE-2026-35521 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-35521 affect?

CVE-2026-35521 affects ftldns. Severity is high (CVSS 8.8). FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface. From 6.0 to before 6.6, the Pi-hole FTL engine contains a Remote Code Execution (RCE) vulnerability in the DHCP hosts configuration p

How urgent is CVE-2026-35521?

Priority 49/100. High severity; Public exploit reference

Software pages

Dnsmasq vulnerabilities

Related CVEs

CVE-2026-35517 HIGH 8.8 UPGRADE FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface
CVE-2026-35491 MEDIUM 6.1 UPGRADE FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface
CVE-2026-35518 HIGH 8.8 UPGRADE FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface
CVE-2026-35520 HIGH 8.8 UPGRADE FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface
CVE-2026-35519 HIGH 8.8 UPGRADE FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface

References

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