CVE-2025-59355: Apache Linkis Information Disclosure Flaw

CVE-2025-59355 Overview

CVE-2025-59355 is an information leakage vulnerability affecting Apache Linkis versions 1.0.0 through 1.7.0. The vulnerability exists in the org.apache.linkis.metadata.util.HiveUtils.decode() function, which logs complete input parameter strings when Base64 decoding fails. If the input contains sensitive information such as Hive Metastore keys or plaintext passwords from configuration files like hive-site.xml, this sensitive data is written to log files in cleartext.

Critical Impact

Sensitive credentials including Hive Metastore passwords and connection keys may be exposed in application logs when Base64 decoding operations fail, potentially leading to unauthorized access to connected data systems.

Affected Products

• Apache Linkis versions 1.0.0 through 1.7.0
• Components utilizing sensitive fields in hive-site.xml (e.g., javax.jdo.option.ConnectionPassword)
• Systems with Base64-encoded configuration values in Hive metadata utilities

Discovery Timeline

• 2026-01-19 - CVE CVE-2025-59355 published to NVD
• 2026-01-20 - Last updated in NVD database

Technical Details for CVE-2025-59355

Vulnerability Analysis

This vulnerability represents a classic CWE-532 (Insertion of Sensitive Information into Log File) issue. The HiveUtils.decode() function in Apache Linkis is designed to decode Base64-encoded configuration values. However, when this decoding operation fails, the error handling logic writes the complete unencoded input string to log files at the ERROR level using logger.error(str + "decode failed", e).

The vulnerability is particularly concerning in environments where configuration items contain sensitive credentials. When an invalid Base64 string is encountered (whether due to corruption, misconfiguration, or encoding issues), the entire raw value—which may include plaintext passwords, API keys, or connection strings—is persisted to disk in application logs.

Root Cause

The root cause is improper error handling in the Base64 decoding routine. Rather than sanitizing or redacting the input parameter before logging, the implementation directly includes the complete input string in error messages. This design flaw violates the principle of never logging potentially sensitive data, regardless of the operation's success or failure status.

Attack Vector

The vulnerability can be exploited under specific conditions:

1. A configuration item in hive-site.xml or similar configuration files contains an invalid Base64 string
2. The HiveUtils.decode() function is called with this malformed input
3. The decoding operation fails, triggering the error logging pathway
4. Log files are accessible to users who should not have access to the sensitive configuration values

An attacker with read access to application logs could extract sensitive credentials that were inadvertently logged during decode failures. This is particularly dangerous in multi-tenant environments or systems where log aggregation services may have broader access than intended.

Detection Methods for CVE-2025-59355

Indicators of Compromise

• Review Apache Linkis log files for entries containing "decode failed" error messages
• Search logs for patterns matching sensitive configuration keys such as javax.jdo.option.ConnectionPassword
• Monitor for unusual access patterns to log directories or log aggregation systems
• Check for Base64 decoding error spikes that may indicate configuration issues triggering the vulnerability

Detection Strategies

• Implement log monitoring rules to detect error patterns containing "decode failed" strings in Linkis logs
• Deploy file integrity monitoring on log directories to detect unauthorized access
• Configure SIEM rules to alert on potential credential exposure patterns in application logs
• Audit log access permissions and ensure proper segregation of duties

Monitoring Recommendations

• Enable access logging for all log file directories and monitor for unauthorized access attempts
• Implement centralized log management with access controls to prevent unauthorized viewing
• Set up alerts for configuration parsing errors that may indicate decoding failures
• Review log retention policies to minimize exposure window of potentially leaked credentials

How to Mitigate CVE-2025-59355

Immediate Actions Required

• Upgrade Apache Linkis to version 1.8.0 or later, which implements desensitized logging
• Review existing log files for exposed credentials and rotate any potentially compromised passwords
• Restrict file system permissions on log directories to authorized personnel only
• Verify that log aggregation and monitoring systems have appropriate access controls

Patch Information

Apache has addressed this vulnerability in Linkis version 1.8.0. The fix replaces the verbose error logging with a sanitized version that no longer includes the input parameter string. The updated logging statement uses logger.error("URL decode failed: {}", e.getMessage()), which outputs only the exception message without the potentially sensitive input data.

For detailed information about the security fix, see the Apache Mailing List Discussion and the Openwall OSS Security Post.

Workarounds

• Implement strict file permissions on log directories to limit access to essential personnel only
• Configure log rotation with short retention periods to minimize the window of credential exposure
• If upgrading is not immediately possible, review and validate all Base64-encoded configuration values to prevent decode failures
• Consider implementing a log scrubbing solution to detect and redact sensitive patterns before logs are persisted

# Restrict log file permissions
chmod 600 /path/to/linkis/logs/*.log
chown linkis:linkis /path/to/linkis/logs/*.log

# Implement aggressive log rotation to limit exposure
# Add to logrotate configuration
cat << EOF > /etc/logrotate.d/linkis
/path/to/linkis/logs/*.log {
    daily
    rotate 7
    compress
    delaycompress
    missingok
    notifempty
    create 600 linkis linkis
}
EOF