Authenticated command execution via upstream newline injection
Published Apr 7, 2026 · Updated Apr 7, 2026
OS command injection in Pi-hole FTL 6.0 through 6.5 allows remote authenticated users to execute commands through the configuration API. The dns.upstreams validator returns success without inspecting values, and fprintf writes embedded newlines into dnsmasq configuration, enabling leasefile-ro and dhcp-script directives that reach popen. Administrative API access and a DNS service restart are required; commands run on the Pi-hole host and can read, alter, or interrupt its DNS service.
Summary
What happened
OS command injection in Pi-hole FTL 6.0 through 6.5 allows remote authenticated users to execute commands through the configuration API. The dns.upstreams validator returns success without inspecting values, and fprintf writes embedded newlines into dnsmasq configuration, enabling leasefile-ro and dhcp-script directives that reach popen. Administrative API access and a DNS service restart are required; commands run on the Pi-hole host and can read, alter, or interrupt its DNS service.
The record
- CVE
- CVE-2026-35517
- Published
- Apr 7, 2026
- Updated
- Apr 7, 2026
- Vendor
- Pi-hole
- Product
- Pi-hole FTL
- Classifications
- CWE-20, CWE-78, CWE-93, T1059.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 7, 2026CVE publishedPublication date reported by the CVE source.
- Apr 7, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 6.0, < 6.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Pi-hole dns.upstreams API proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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