KibanaApplication · Elastic
CVE-2026-42401
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 · uneditedImproper Neutralization of Input During Web Page Generation (CWE-79) in Kibana can lead to stored HTML injection. A user with write access to an Elasticsearch index could persist crafted markup which, when subsequently rendered through an affected Kibana view by another user, was not sufficiently sanitized. Successful exploitation could result in unauthorized UI manipulation and outbound network requests issued from the viewing user's browser session.
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 confidenceThis is a stored HTML injection (CWE-79, Cross-Site Scripting) vulnerability in Kibana where user-supplied content written to Elasticsearch indexes is rendered in Kibana's UI without proper sanitization. An attacker with write access to an index can embed malicious HTML/JavaScript that executes in the browsers of other users who subsequently view that data through affected Kibana interfaces, enabling UI manipulation and unauthorized outbound network requests.
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
KibanaApplication
>= 8.0.0, < 8.19.16>= 9.0.0, < 9.3.5CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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.
-
Determine installed Kibana versionRun 'kibana --version' or check the version file in the Kibana installation directory (e.g., /usr/share/kibana/package.json). On managed deployments, use the Kibana API endpoint GET /api/status to retrieve the version number from the response.Affected if The installed version is 8.0.0 or higher but below 8.19.16, OR 9.0.0 or higher but below 9.3.5.
-
Identify data viewing interfaces in useReview which Kibana features are actively used: Discover (data exploration), Visualize (saved searches/visualizations), Dashboard, Lens, or any custom data views. Check for saved searches or saved objects that retrieve raw fields from Elasticsearch.Affected if Kibana is configured with data views, saved searches, or visualizations that display raw field content from Elasticsearch indexes.
-
Check index write access policiesReview Elasticsearch index permissions to determine which users or roles have write or create access to indexes. Check role-based access control (RBAC) definitions in Elasticsearch/ Kibana security settings.Affected if Any user or service account has write access to Elasticsearch indexes that are then visualized through Kibana.
-
Inspect data rendering behaviorExamine whether the affected Kibana interfaces render field values as raw HTML or plain text. In Discover or saved searches, check if field value formatting is set to use 'Short Dots' or raw formatting that may bypass default escaping.Affected if Field formatters are configured to render content in a way that could bypass default HTML encoding (e.g., custom formatters, markdown rendering enabled).
A user is affected if their Kibana version falls within the vulnerable ranges AND they have Kibana interfaces that render data from Elasticsearch indexes where untrusted users have write access.
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.
dbcve · scoped8.19.169.3.5
Upgrade Kibana to the patched version provided by Elastic's security advisory, or implement output encoding/sanitization for data retrieved from Elasticsearch before rendering in the Kibana UI.
Kibana 8.19.16 (or 8.x latest) / Kibana 9.3.5 (or 9.x latest)
- 1. Back up all Kibana configuration files, dashboards, and any custom plugins
- 2. Review Elastic Stack upgrade documentation for your current version
- 3. Plan maintenance window - Kibana will be unavailable during upgrade
- 4. For Kibana 8.x deployments: Upgrade to version 8.19.16 or later
- 5. For Kibana 9.x deployments: Upgrade to version 9.3.5 or later
- 6. Ensure Elasticsearch version is compatible with the target Kibana version before upgrading
- 7. After upgrade, verify Kibana starts successfully and all dashboards load correctly
- 8. Test that stored content from Elasticsearch indexes renders correctly in the upgraded Kibana
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Kibana
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 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 $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42401 — 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-2026-42401 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