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CVE-2026-40557: CWE-295 Improper Certificate Validation in Apache Software Foundation Apache Storm Prometheus Reporter

0
Medium
VulnerabilityCVE-2026-40557cvecve-2026-40557cwe-295
Published: Mon Apr 27 2026 (04/27/2026, 13:12:11 UTC)
Source: CVE Database V5
Vendor/Project: Apache Software Foundation
Product: Apache Storm Prometheus Reporter

Description

Improper Certificate Validation via Global SSL Context Downgrade in Apache Storm Prometheus Reporter Versions Affected: from 2.6.3 to 2.8.6 Description:  In production deployments where an administrator enables storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validation (by default it is disabled) intending to affect only the Prometheus reporter, the undocumented global side effect creates an attack surface across every TLS-protected communication channel in the Storm daemon. The PrometheusPreparableReporter class implements an INSECURE_TRUST_MANAGER that accepts all SSL certificates without validation, with empty checkClientTrusted and checkServerTrusted methods. Most critically, when the storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validation configuration option is enabled (default = disabled) for HTTPS Prometheus PushGateway connections, the INSECURE_CONNECTION_FACTORY calls SSLContext.setDefault(sslContext), which globally replaces the JVM's default SSL context rather than applying the insecure context only to the Prometheus connection. This payload flows through storm.yaml configuration → PrometheusPreparableReporter.prepare() → INSECURE_CONNECTION_FACTORY → SSLContext.setDefault(), resulting in a JVM-wide TLS security downgrade. All subsequent HTTPS connections in the process - including ZooKeeper, Thrift, Netty, and UI connections - silently trust all certificates, including self-signed, expired, and attacker-generated ones, enabling man-in-the-middle interception of cluster state, topology submissions, tuple data, and administrative credentials. Mitigation: 2.x users should upgrade to 2.8.7 if the Prometheus Metrics Reporter is used. Prometheus Metrics Reporter Users who cannot upgrade immediately should remove the storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validation: true setting from their storm.yaml configuration and instead configure a proper truststore containing the PushGateway's certificate.

CVSS v3.1

Score 4.8medium

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected software

Affected versions
=2.6.3

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 05/05/2026, 02:13:11 UTC

Technical Analysis

The vulnerability arises from the PrometheusPreparableReporter class in Apache Storm Prometheus Reporter, which implements an insecure trust manager that accepts all SSL certificates without validation. When the configuration storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validation is set to true, the insecure SSL context is set globally via SSLContext.setDefault(), impacting all TLS connections in the JVM process. This results in a JVM-wide TLS security downgrade, allowing man-in-the-middle interception of sensitive data across various Storm daemon components. The issue affects versions 2.6.3 through 2.8.6 and is resolved in version 2.8.7.

Potential Impact

The vulnerability allows an attacker to perform man-in-the-middle attacks on all TLS-protected communications within the Storm daemon process, including ZooKeeper, Thrift, Netty, UI connections, and Prometheus PushGateway connections. This can lead to interception and potential compromise of cluster state, topology submissions, tuple data, and administrative credentials. The CVSS score is 4.8 (medium severity), reflecting limited impact on confidentiality and integrity with no impact on availability.

Mitigation Recommendations

A fix is available in Apache Storm version 2.8.7. Users of affected versions who utilize the Prometheus Metrics Reporter should upgrade to 2.8.7. If immediate upgrade is not possible, users must remove the configuration setting storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validation: true from their storm.yaml file and instead configure a proper truststore containing the PushGateway's certificate to ensure secure TLS validation.

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Technical Details

Data Version
5.2
Assigner Short Name
apache
Date Reserved
2026-04-14T11:20:51.218Z
Cvss Version
null
State
PUBLISHED
Remediation Level
null

Threat ID: 69ef64deba26a39fba2863c8

Added to database: 4/27/2026, 1:30:06 PM

Last enriched: 5/5/2026, 2:13:11 AM

Last updated: 6/11/2026, 6:27:06 PM

Views: 71

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