CVE-2026-34487 is a high-severity (CVSS 7.5) CWE-532 vulnerability in org.apache.tomcat:tomcat-tribes. A fix is available for org.apache.tomcat:tomcat-tribes — see the affected versions and patch details below.
Apache Tomcat: Cloud membership for clustering component exposed the Kubernetes bearer token
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-34487.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.tomcat:tomcat-tribes☕org.apache.tomcat:tomcat-tribes☕org.apache.tomcat:tomcat-tribes☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat.embed:tomcat-embed-core☕org.apache.tomcat.embed:tomcat-embed-core+1 moreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.tomcat:tomcat-tribes | ≥ 9.0.13&&< 9.0.117 | 9.0.117org.apache.tomcat:tomcat-tribes:9.0.117 |
| ☕Maven | org.apache.tomcat:tomcat-tribes | ≥ 10.1.0-M1&&< 10.1.54 | 10.1.54org.apache.tomcat:tomcat-tribes:10.1.54 |
| ☕Maven | org.apache.tomcat:tomcat-tribes | ≥ 11.0.0-M1&&< 11.0.21 | 11.0.21org.apache.tomcat:tomcat-tribes:11.0.21 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 9.0.13&&< 9.0.117 | 9.0.117org.apache.tomcat:tomcat:9.0.117 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 10.1.0-M1&&< 10.1.54 | 10.1.54org.apache.tomcat:tomcat:10.1.54 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 11.0.0-M1&&< 11.0.21 | 11.0.21org.apache.tomcat:tomcat:11.0.21 |
Affected Products
tomcatapacheDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat-tribes, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.tomcat:tomcat-tribes to 9.0.117 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34487 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Low impact. This vulnerability in Apache Tomcat affects the cloud membership for clustering component, potentially exposing Kubernetes bearer tokens in log files. Exploitation requires the cloud membership feature to be enabled and an attacker to have access to the system's log files. Red Hat Enterprise Linux versions…
Disable the cloud membership for clustering feature in Apache Tomcat if it is not actively used. Additionally, ensure that access to Apache Tomcat log files is strictly controlled and limited to authorized personnel only to prevent unauthorized disclosure of sensitive information. If the cloud membership for clustering feature is disabled, a restart of the Apache Tomcat service may be required for the changes to take effect.Source: Red Hat security advisory for CVE-2026-34487 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | tomcat9-1:9.0.117-1.el10_2 | RHSA-2026:25341 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | tomcat9-1:9.0.120-1.el10_0 | RHSA-2026:67163 |
| Red Hat Enterprise Linux 8 | tomcat-1:9.0.120-1.el8_10 | RHSA-2026:68677 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | tomcat-1:9.0.120-1.el8_8 | RHSA-2026:68680 |
| Red Hat Enterprise Linux 9 | tomcat-1:9.0.117-1.el9_8 | RHSA-2026:26323 |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | tomcat-1:9.0.120-1.el9_2 | RHSA-2026:68678 |
| Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | tomcat-1:9.0.120-1.el9_4 | RHSA-2026:68679 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | tomcat-1:9.0.120-1.el9_6 | RHSA-2026:68659 |
Frequently Asked Questions
Is CVE-2026-34487 in your dependencies?
Find it across Maven, including transitive dependencies.