CVE-2026-7860: Vaadin Plugin Information Disclosure Flaw

CVE-2026-7860 Overview

CVE-2026-7860 is an information disclosure vulnerability affecting the Vaadin Maven plugin and Vaadin Gradle plugin. The flaw causes the plugins to log the full set of environment variables to build output whenever the frontend build process exits with a non-zero status. Continuous integration (CI) environments commonly inject credentials, API tokens, and signing keys as environment variables, so any failed frontend build can expose those secrets in clear text within CI logs and archived build artifacts. The issue is tracked under [CWE-209] Generation of Error Message Containing Sensitive Information.

Critical Impact

Failed frontend builds emit all process environment variables to logs, leaking CI/CD secrets such as deployment tokens, registry credentials, and signing keys to anyone with log access.

Affected Products

• com.vaadin:flow-plugin-base versions 23.0.0–23.6.10, 24.0.0–24.10.3, and 25.0.0–25.1.4
• com.vaadin:flow-maven-plugin versions 23.0.0–23.6.10, 24.0.0–24.10.3, and 25.0.0–25.1.4
• com.vaadin:flow-gradle-plugin versions 24.0.0–24.10.3 and 25.0.0–25.1.4

Discovery Timeline

• 2026-05-19 - CVE-2026-7860 published to NVD
• 2026-05-19 - Last updated in NVD database

Technical Details for CVE-2026-7860

Vulnerability Analysis

The Vaadin build plugins delegate the frontend asset compilation step to an external Node.js process. When that child process terminates with a non-zero exit code, the plugin's error-reporting path serializes the complete process environment into the build log to aid troubleshooting. The environment block typically includes every variable inherited from the CI runner, including secrets that orchestration platforms inject for the duration of the job.

The vulnerability is categorized as information exposure through an error message [CWE-209]. Exploitation does not require an attacker to actively trigger the flaw. Any transient frontend build failure, such as a broken dependency, network timeout, or syntax error, is sufficient to surface secrets. Once written, the variables persist in CI history, archived artifacts, and downstream log aggregation systems.

Root Cause

The plugin's failure handler prints the child process environment without filtering or redaction. There is no allowlist of safe variables and no pattern-based suppression for names containing tokens such as SECRET, TOKEN, KEY, or PASSWORD. The behavior is unconditional on non-zero exit status from the Node.js frontend build invocation.

Attack Vector

The attack vector is local and requires read access to build logs or artifacts. An attacker who can view CI job output, pull request build summaries, or stored artifact bundles can extract secrets from any failed Vaadin frontend build. In multi-tenant CI environments or projects with public build logs, this widens the disclosure scope to unauthenticated viewers. The vulnerability does not produce executable code paths and is not directly exploitable for code execution.

The vulnerability manifests in the error-reporting branch of the frontend build invocation. See the Vaadin Security Advisory and the GitHub Pull Request for the corrective patch details.

Detection Methods for CVE-2026-7860

Indicators of Compromise

• Build log entries from flow-maven-plugin or flow-gradle-plugin containing blocks of KEY=VALUE pairs immediately following a frontend build failure message.
• Presence of variables named *_TOKEN, *_SECRET, *_PASSWORD, AWS_*, GITHUB_TOKEN, or NPM_TOKEN in archived CI logs.
• Unexpected use of credentials originally provisioned only to CI runners appearing in external systems after a failed Vaadin build.

Detection Strategies

• Scan historical CI logs and archived build artifacts for environment variable dumps tied to the Vaadin frontend build step.
• Run secret-scanning tools such as gitleaks or trufflehog against CI log archives, not only source repositories.
• Correlate failed Vaadin build events with downstream authentication anomalies in cloud and registry audit trails.

Monitoring Recommendations

• Enable log redaction features in the CI platform (GitHub Actions, GitLab CI, Jenkins) for any string registered as a secret.
• Alert on retrieval of build logs and artifacts from jobs that contain Vaadin plugin failure markers.
• Rotate CI-scoped credentials on a fixed cadence and after each confirmed frontend build failure on vulnerable plugin versions.

How to Mitigate CVE-2026-7860

Immediate Actions Required

• Upgrade com.vaadin:flow-maven-plugin and com.vaadin:flow-plugin-base to 23.6.11, 24.10.4, or 25.1.5 or later, matching your major version line.
• Upgrade com.vaadin:flow-gradle-plugin to 24.10.4 or 25.1.5 or later.
• Audit all CI logs and archived build artifacts generated by vulnerable plugin versions for exposed secrets.
• Rotate any credential that may have been present in the build environment during a failed Vaadin frontend build.

Patch Information

Vaadin has released fixed versions on all three supported branches. Upgrade to 23.6.11 or newer for the 23.x line, 24.10.4 or newer for the 24.x line, and 25.1.5 or newer for the 25.x line. Vaadin versions 10–13 and 15–22 are no longer supported and must be migrated to 23, 24, or 25 to receive the fix. Patch details are available in the Vaadin Security Advisory and the upstream GitHub Pull Request.

Workarounds

• Configure the CI runner to inject secrets only into the specific steps that require them, removing them from the environment visible to the Vaadin build step.
• Restrict read access to CI logs and artifact storage to authorized personnel and disable public log visibility on open-source projects.
• Enable platform-native secret masking and confirm that masked values cover all credential variables consumed by builds.

# Configuration example: upgrade pinned Vaadin plugin versions in pom.xml or build.gradle
# Maven (pom.xml)
# <plugin>
#   <groupId>com.vaadin</groupId>
#   <artifactId>flow-maven-plugin</artifactId>
#   <version>24.10.4</version>
# </plugin>

# Gradle (build.gradle)
# plugins {
#   id 'com.vaadin' version '24.10.4'
# }