CVE-2018-6536
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 · uneditedAn issue was discovered in Icinga 2.x through 2.8.1. The daemon creates an icinga2.pid file after dropping privileges to a non-root account, which might allow local users to kill arbitrary processes by leveraging access to this non-root account for icinga2.pid modification before a root script executes a "kill `cat /pathname/icinga2.pid`" command, as demonstrated by icinga2.init.d.cmake.
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 confidenceIcinga 2.x creates its pid file after dropping privileges to a non-root service account. An attacker with access to this non-root account can modify the pid file to contain an arbitrary process ID. When the init script (running as root) executes 'kill `cat /pathname/icinga2.pid`' to stop the service, it will terminate the wrong process, potentially causing denial of service or disrupting critical system processes.
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>= 2.0.0, <= 2.8.1CVSS 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
- None
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
-
Check installed Icinga 2 versionRun 'icinga2 --version' or 'rpm -q icinga2' / 'dpkg -l icinga2' depending on your systemAffected if The version returned is between 2.0.0 and 2.8.1 inclusive
-
Locate the Icinga 2 pid fileCheck the pid file path in the Icinga 2 configuration (typically /var/run/icinga2/icinga2.pid or /run/icinga2/icinga2.pid) or inspect the running process for the actual pid file path using 'ps aux | grep icinga2'Affected if A pid file exists at the expected location and is readable/writable by the icinga2 service account
-
Verify pid file ownership and permissionsRun 'ls -la /var/run/icinga2/icinga2.pid' or check the equivalent path to see ownership and permissionsAffected if The pid file is owned by the non-root icinga2 service account rather than root, indicating it was created after privilege dropping
-
Check if pid file is created before privilege droppingReview the Icinga 2 init script or service configuration to determine the order of operations, or examine the runtime behavior during service startupAffected if The pid file is created after Icinga 2 drops privileges to a non-root user account
You are affected if you are running Icinga 2 version 2.0.0 through 2.8.1 and the pid file is owned by the non-root service account, allowing that account to modify it and cause the init script to kill unintended processes.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade to Icinga 2.8.2 or later where the pid file is created before dropping privileges, or ensure the pid file location has restricted permissions to prevent modification by the non-root account.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-6536 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-6536 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data