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FtldnsApplication · Pi Hole

CVE-2026-35491

MEDIUM · 6.1 CVSS v3.1 Published 2026-04-07
Fix available
A fix is available. Upgrade to 6.6 or later.
See remediation →
63/100
Remediation priority · Elevated
Public exploit Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
FTLDNS (pihole-FTL) provides an interactive API and also generates statistics for Pi-hole's Web interface. From 6.0 to before 6.6, Pi-hole FTL supports a CLI password feature (webserver.api.cli_pw) that creates “CLI” API sessions intended to be read-only for configuration changes. While /api/config correctly blocks CLI sessions from mutating configuration, /api/teleporter allowed Teleporter imports for CLI sessions, enabling a CLI-scoped session to overwrite configuration via a Teleporter archive (authorization bypass). This vulnerability is fixed in 6.6.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-863

An authorization check exists but is flawed, so it passes when it should fail. Attackers probe roles and object references to find the gap. Remediation means centralising and correctly implementing the access-control logic, then testing it against every role.

General guidance for the incorrect authorization class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FtldnsApplication
Affected:>= 6.0, < 6.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
Low

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.6 or later
Fixed in 6.6
Recommended fix High confidence

6.6

  1. Backup your current Pi-hole configuration and any custom settings before upgrading
  2. Stop the pihole-FTL service to ensure a clean upgrade process
  3. Update your package repository to ensure you have access to the latest packages
  4. Upgrade Ftldns to version 6.6 using your system's package manager (e.g., apt update && apt install pihole-ftl or the equivalent for your distribution)
  5. Verify that the upgrade completed successfully by checking the installed version (pihole-FTL -v)
  6. Restart the pihole-FTL service to apply the updated binaries
  7. Test that the /api/teleporter endpoint now properly rejects CLI session requests (authorization should be enforced)

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-35491 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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