CVE-2019-12303
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 · uneditedIn Rancher 2 through 2.2.3, Project owners can inject additional fluentd configuration to read files or execute arbitrary commands inside the fluentd container.
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 confidenceIn Rancher 2 through 2.2.3, users with Project owner permissions can modify fluentd logging configuration to achieve arbitrary command execution inside the fluentd container. This represents a privilege escalation vulnerability where a restricted role can escape its intended sandbox.
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, <= 2.2.3CVSS 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
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify Rancher server versionAccess the Rancher UI and check the version displayed in the bottom-left corner, or query the Rancher API at /v1/management.cattle.io.setting/first-login or use the CLI: rancher --versionAffected if The installed version is >= 2.0.0 and <= 2.2.3
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Verify logging feature is enabledNavigate to a project's settings in Rancher UI: select a project, go to Tools > Logging. Alternatively, query the Kubernetes cluster for fluentd pods: kubectl get pods -n cattle-logging -l app.kubernetes.io/name=fluentdAffected if Fluentd logging is enabled for any project in the Rancher environment
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Check Project owner role bindingsList all RoleBindings or ClusterRoleBindings in Rancher that assign the project-owner role. Use kubectl: kubectl get rolebindings -A | grep project-owner, or inspect Rancher project membership via the UI under Project > MembersAffected if Any user or service account is bound to the Project owner role in any project that has logging enabled
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Examine fluentd configuration for dangerous settingsIf fluentd is running, inspect the fluentd configmap or container configuration. Run: kubectl get configmap -n cattle-logging fluentd -o yaml, and look for exec_config or filter_grep sections that could contain command execution patternsAffected if The fluentd configuration contains @filter or @output plugins that execute external commands, or allows Project owners to modify such configuration
A user is affected if their Rancher server version is between 2.0.0 and 2.2.3 AND they have the fluentd logging feature enabled with Project owner roles assigned to non-administrative users.
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 Rancher to a version newer than 2.2.3. If immediate upgrading is not feasible, review and restrict Project owner role permissions to prevent configuration modification.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-12303 — 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-2019-12303 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
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- 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
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