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Pi HoleApplication

CVE-2026-33727

MEDIUM · 6.7 CVSS v3.1 Published 2026-04-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
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
Pi-hole is a Linux network-level advertisement and Internet tracker blocking application. Version 6.4 has a local privilege-escalation vulnerability allows code execution as root from the low-privilege pihole account. Important context: the pihole account uses nologin, so this is not a direct interactive-login issue. However, nologin does not prevent code from running as UID pihole if a Pi-hole component is compromised. In that realistic post-compromise scenario, attacker-controlled content in /etc/pihole/versions is sourced by root-run Pi-hole scripts, leading to root code execution. This vulnerability is fixed in 6.4.1.

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 · high confidence

Pi-hole 6.4 contains a local privilege escalation vulnerability where attacker-controlled content in /etc/pihole/versions gets sourced by root-run Pi-hole scripts. In a post-compromise scenario where an attacker has already achieved code execution as the low-privilege pihole UID, they can inject malicious content into the versions file that will be executed with root privileges when root-run scripts source it.

MitigationUpgrade to Pi-hole version 6.4.1 or later to patch this vulnerability. In the interim, ensure that the pihole user cannot modify files in /etc/pihole/ and monitor for unauthorized modifications to /etc/pihole/versions.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
Pi HoleApplication
Affected:= 6.4

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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Pi-hole version
    Run `pihole -v` or check the package manager for the installed pi-hole-core package version
    Affected if The installed version is exactly 6.4 (versions prior to 6.4.1 are affected)
  2. Verify /etc/pihole/versions exists
    Check if the file /etc/pihole/versions is present on the system using `ls -la /etc/pihole/versions`
    Affected if The file exists and the system runs Pi-hole 6.4
  3. Check pihole user write access
    Run `ls -la /etc/pihole/` and examine ownership and permissions. Check if the pihole user has write permission to the versions file or its parent directory
    Affected if The pihole user can write to /etc/pihole/versions or the directory containing it
  4. Inspect versions file content
    View the contents of /etc/pihole/versions using `cat /etc/pihole/versions` and look for unexpected commands, shell execution syntax, or content not generated by standard Pi-hole operations
    Affected if The file contains suspicious commands, function definitions, or content that was not added by legitimate Pi-hole updates

A system is affected if it runs Pi-hole version 6.4 and the pihole user has write access to /etc/pihole/versions, allowing injection of content that will execute with root privileges.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Pi-hole version 6.4.1 or later to patch this vulnerability. In the interim, ensure that the pihole user cannot modify files in /etc/pihole/ and monitor for unauthorized modifications to /etc/pihole/versions.

Recommended fix High confidence

6.4.1

  1. Back up your Pi-hole configuration using `pihole -a backup` or by copying /etc/pihole/ directory
  2. Run the Pi-hole update script: `pihole -up` or `sudo pihole -up`
  3. Verify the upgrade was successful by checking the version: `pihole -v`
  4. Confirm the version shows 6.4.1
  5. Verify the /etc/pihole/versions file permissions are correct (should not be writable by the pihole user)

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

Fix this in Pi Hole Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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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-2026-33727 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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