How severe is CVE-2026-34486?

CVE-2026-34486 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-34486?

CVE-2026-34486 affects the following packages: org.apache.tomcat:tomcat-tribes (Maven), org.apache.tomcat:tomcat-tribes (Maven), org.apache.tomcat:tomcat-tribes (Maven), org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-34486?

Update org.apache.tomcat:tomcat-tribes to 11.0.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34486 is resolved across your whole dependency graph.

How do I detect CVE-2026-34486 in my Maven dependencies?

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.

How do I mitigate CVE-2026-34486 if there is no patch (or I can't update yet)?

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.

Is CVE-2026-34486 actively exploited in the wild?

Yes. There are 3 known exploit references for CVE-2026-34486, including . All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2026-34486?

CVE-2026-34486 has an EPSS (Exploit Prediction Scoring System) score of 98.5%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2026-34486 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2026-34486 (Apache Tomcat Missing Encryption of Sensitive Data Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-08-04. CISA required all US federal civilian agencies to remediate this vulnerability by 2026-08-07. The required action was: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2026-34486?

CVE-2026-34486 is classified as CWE-311 (CWE-311), CWE-807 (CWE-807). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2026-34486?

A Nuclei detection template exists for CVE-2026-34486, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2026-34486 published, and has it been updated?

CVE-2026-34486 was published on April 9, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

CISA KEV · ACTIVELY EXPLOITED

HIGH severity

CVE-2026-34486 — tomcat-tribes

HIGHFix: apache/tomcat@1fab40c

CVE-2026-34486 is a high-severity (CVSS 7.5) CWE-311 vulnerability in org.apache.tomcat:tomcat-tribes. It is in CISA's Known Exploited Vulnerabilities catalog (added 2026-08-04) — treat it as actively exploited and patch now. A fix is available for org.apache.tomcat:tomcat-tribes — see the affected versions and patch details below.

Apache Tomcat: Fix for CVE-2026-29146 allowed bypass of EncryptInterceptor

Also known asBIT-tomcat-2026-34486GHSA-69r9-qgr7-g2wj

Published

Apr 9, 2026

Updated

Oct 28, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

3 known

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-08-04. Federal agencies were required to remediate by 2026-08-07.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2026-34486.

EPSS Exploitation Probability

via FIRST.org ↗

98.5%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

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

6 pkgs affected

☕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

Real-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

Missing Encryption of Sensitive Data vulnerability in Apache Tomcat due to the fix for CVE-2026-29146 allowing the bypass of the EncryptInterceptor.

This issue affects Apache Tomcat: 11.0.20, 10.1.53, 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

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.tomcat:tomcat-tribes`	≥ 11.0.20&&< 11.0.21	11.0.21`org.apache.tomcat:tomcat-tribes:11.0.21`
☕Maven	`org.apache.tomcat:tomcat-tribes`	≥ 10.1.53&&< 10.1.54	10.1.54`org.apache.tomcat:tomcat-tribes:10.1.54`
☕Maven	`org.apache.tomcat:tomcat-tribes`	≥ 9.0.116&&< 9.0.117	9.0.117`org.apache.tomcat:tomcat-tribes:9.0.117`
☕Maven	`org.apache.tomcat:tomcat`	≥ 11.0.20&&< 11.0.21	11.0.21`org.apache.tomcat:tomcat:11.0.21`
☕Maven	`org.apache.tomcat:tomcat`	≥ 10.1.53&&< 10.1.54	10.1.54`org.apache.tomcat:tomcat:10.1.54`
☕Maven	`org.apache.tomcat:tomcat`	≥ 9.0.116&&< 9.0.117	9.0.117`org.apache.tomcat:tomcat:9.0.117`

Affected Products

7 products · 14 configurations

Application

tomcatapache

3 versions

9.0.11610.1.5311.0.20

enterprise linuxredhat

3 versions

8.09.010.0

enterprise linux elsredhat

1 version

7.0

enterprise linux eusredhat

1 version

10.0

enterprise linux tusredhat

1 version

8.8

enterprise linux update services for sap solutionsredhat

4 versions

8.89.29.49.6

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

striga-ai/CVE-2026-34486

EncryptInterceptor fail-open bypass in Apache Tomcat Tribes clustering l

⭐ 69🍴 14Sep 2026

AirSkye/CVE-2026-34486-poc

CVE-2026-34486 Apache Tomcat EncryptInterceptor 绕过漏洞复现（使用GLM5.1复现完成）

⭐ 12🍴 1Aug 2026

404-src/CVE-2026-34486

Apache Tomcat EncryptInterceptor Bypass → Unauthenticated RCE (CVE-2026-

⭐ 9🍴 6Sep 2026

Detection & mitigation playbook

Open-source dependency

Detect
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 11.0.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34486 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.

How to detect CVE-2026-34486

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2026-34486 -u https://target

Template: Apache Tomcat Tribes EncryptInterceptor Bypass - Remote Code Execution
Severity: critical
Impact: An unauthenticated attacker can achieve remote code execution by sending an unencrypted serialized Java object to the Tribes cluster receiver port.
Remediation: Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117, which fix the issue.

Template by ProjectDiscovery nuclei-templates (DhiyaneshDk), MIT licensed. View the full template. Scan only systems you are authorised to test.

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.

Red HatImportant

This is an Important flaw in Apache Tomcat where a bypass in the EncryptInterceptor allows sensitive data to remain unencrypted. This could lead to information disclosure in Red Hat Enterprise Linux and Red Hat JBoss Web Server environments utilizing affected versions of Apache Tomcat.

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for CVE-2026-34486 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Enterprise Linux 10	`tomcat-1:10.1.49-3.el10_2`	RHSA-2026:36788
Red Hat Enterprise Linux 10	`tomcat9-1:9.0.117-2.el10_2`	RHSA-2026:36790
Red Hat Enterprise Linux 10.0 Extended Update Support	`tomcat-1:10.1.36-2.el10_0`	RHSA-2026:36787
Red Hat Enterprise Linux 10.0 Extended Update Support	`tomcat9-1:9.0.87-6.el10_0`	RHSA-2026:36789
Red Hat Enterprise Linux 7 Extended Lifecycle Support	`tomcat-0:7.0.76-18.el7_9`	RHSA-2026:38505
Red Hat Enterprise Linux 8	`tomcat-1:9.0.87-2.el8_10`	RHSA-2026:37137
Red Hat Enterprise Linux 8.8 Telecommunications Update Service	`tomcat-1:9.0.87-2.el8_8`	RHSA-2026:37136
Red Hat Enterprise Linux 9	`tomcat-1:9.0.117-2.el9_8`	RHSA-2026:36879

Frequently Asked Questions

Missing Encryption of Sensitive Data vulnerability in Apache Tomcat due to the fix for CVE-2026-29146 allowing the bypass of the EncryptInterceptor. This issue affects Apache Tomcat: 11.0.20, 10.1.53, 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117, which fix the issue.

O3 Security · Impact-Aware SCA

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CVE-2026-34486 — tomcat-tribes

Exploitation Status

Actively exploited in the wild

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

How to detect CVE-2026-34486

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2026-34486 in your dependencies?