dbcve.org
TomcatWeb server / proxy · Apache

CVE-2026-34487

HIGH · 7.5 CVSS v3.1 Published 2026-04-09
Fix available
A fix is available. Upgrade to 9.0.117 / 10.1.54 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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
Insertion of Sensitive Information into Log File vulnerability in the cloud membership for clustering component of Apache Tomcat exposed the Kubernetes bearer token. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.13 through 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117, which fix the issue.

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

The cloud membership clustering component in Apache Tomcat inadvertently logs Kubernetes bearer tokens to files. An attacker with access to Tomcat logs could retrieve these tokens and gain unauthorized access to the Kubernetes cluster. This affects clustering functionality in Kubernetes-deployed Tomcat instances across versions 9.x, 10.1.x, and 11.x.

MitigationUpgrade to Apache Tomcat 9.0.117, 10.1.54, or 11.0.21. Additionally, rotate any Kubernetes bearer tokens that may have been exposed in logs since the vulnerability was present.

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
TomcatWeb server / proxy
Affected:>= 9.0.13, < 9.0.117>= 10.1.0, < 10.1.54>= 11.0.0, < 11.0.21

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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

  1. Identify installed Tomcat version
    Run 'catalina.sh version' or check the SERVER_RELEASE_KEY file in the Tomcat lib directory, or examine the bootstrap.jar version attribute
    Affected if The version falls within 9.0.13-9.0.116, 10.1.0-10.1.53, or 11.0.0-11.0.20
  2. Verify clustering is configured
    Examine the server.xml or context.xml for <Cluster> elements, and check for cluster-related context attributes in web.xml
    Affected if A <Cluster> element is defined in server.xml or clustering is enabled via context.xml
  3. Confirm Kubernetes deployment
    Check for the presence of /var/run/secrets/kubernetes.io/serviceaccount/ directory, or check for KUBERNETES_SERVICE_ACCOUNT_TOKEN or similar Kubernetes-related environment variables
    Affected if Tomcat is running inside a Kubernetes pod with service account tokens mounted
  4. Examine Tomcat logs for bearer tokens
    Search log files (catalina.out, localhost.log, or custom logs) for patterns matching 'Bearer', 'Bearer token', or JWT-style tokens in Authorization headers
    Affected if Log files contain Kubernetes bearer tokens or Authorization headers with token values

You are affected if you run an affected Tomcat version with clustering enabled in Kubernetes and your logs contain exposed bearer tokens.

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
Upgrade available Upgrade to 9.0.117 / 10.1.54 / 11.0.21 or later
Fixed in 9.0.11710.1.5411.0.21
Interim mitigation

Upgrade to Apache Tomcat 9.0.117, 10.1.54, or 11.0.21. Additionally, rotate any Kubernetes bearer tokens that may have been exposed in logs since the vulnerability was present.

Recommended fix High confidence

Upgrade to Apache Tomcat 9.0.117 (for 9.x line), 10.1.54 (for 10.1.x line), or 11.0.21 (for 11.x line)

  1. Identify your current Tomcat version line (9.x, 10.1.x, or 11.x) by checking the $CATALINA_HOME/README or server info
  2. Stop the Tomcat service before upgrading
  3. Back up your existing Tomcat installation directory, configuration files, and deployed applications
  4. Download the appropriate fixed version: 9.0.117, 10.1.54, or 11.0.21 from the official Apache Tomcat download page (tomcat.apache.org)
  5. Extract the new version to a temporary location
  6. Copy custom configuration files from the backed-up conf directory to the new installation (server.xml, context.xml, etc.)
  7. Deploy your applications from the backed-up webapps directory to the new installation
  8. Start the Tomcat service and verify the application functions correctly
Caveat Minor version upgrades within the same major.minor line typically have no breaking changes; ensure custom configurations are compatible before deploying to production

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

Fix this in Tomcat Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

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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-2026-34487 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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