CVE-2026-23370: Linux Kernel Information Disclosure Flaw

CVE-2026-23370 Overview

CVE-2026-23370 is an information disclosure vulnerability in the Linux kernel's Dell WMI Sysman driver (dell-wmi-sysman). The vulnerability exists in the set_new_password() function, which performs a hex dump of the entire buffer containing plaintext password data. This behavior inadvertently exposes sensitive credentials, including both current and new passwords, potentially allowing local attackers to harvest authentication credentials from system logs or debug output.

Critical Impact

Plaintext passwords including current and new credentials may be exposed through kernel debug output, enabling credential theft and unauthorized system access on Dell systems.

Affected Products

• Linux kernel with Dell WMI Sysman driver (platform/x86: dell-wmi-sysman)
• Dell systems utilizing WMI-based system management interfaces
• Linux distributions running affected kernel versions on Dell hardware

Discovery Timeline

• 2026-03-25 - CVE-2026-23370 published to NVD
• 2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-23370

Vulnerability Analysis

This vulnerability falls under the Information Disclosure category, specifically affecting how the Dell WMI Sysman driver handles sensitive credential data during password change operations. The set_new_password() function in the dell-wmi-sysman driver was designed to facilitate BIOS and system password management through WMI (Windows Management Instrumentation) interfaces on Dell hardware running Linux.

The problematic behavior occurs when the function performs diagnostic hex dumps of data buffers that contain plaintext passwords. This debugging mechanism, while useful during development, creates a significant security risk in production environments. When a user or administrator changes their system password, both the current password and the new password are temporarily stored in a buffer that gets dumped in hexadecimal format.

Root Cause

The root cause is improper handling of sensitive data in the Dell WMI Sysman driver's password management routines. The set_new_password() function included debug logging that performed a complete hex dump of the password buffer without sanitizing or masking the sensitive credential data. This represents a violation of secure coding practices that mandate sensitive information such as passwords should never be written to logs, debug output, or any other persistent storage in plaintext or easily reversible formats.

Attack Vector

The attack vector for this vulnerability is local, requiring an attacker to have access to kernel log output, debug messages, or system logging facilities on an affected Dell system. An attacker with local access could monitor kernel messages via dmesg, system logs in /var/log/, or other logging facilities to capture the hex-dumped password data. Once captured, the hexadecimal data can be trivially converted back to the original plaintext passwords.

Exploitation scenarios include:

• A malicious local user monitoring kernel debug output during password change operations
• An attacker with access to system logs harvesting historically stored password dumps
• Privilege escalation through captured administrative credentials

The vulnerability does not require any special privileges beyond read access to kernel logs or debug output, making it accessible to lower-privileged local attackers on multi-user systems.

Detection Methods for CVE-2026-23370

Indicators of Compromise

• Unexpected hex dump entries in kernel logs (dmesg) related to dell-wmi-sysman operations
• Suspicious access patterns to /var/log/kern.log or similar kernel log files
• Evidence of password buffer content in system debugging output
• Unusual user activity involving repeated access to kernel message buffers

Detection Strategies

• Monitor access to kernel log files for unauthorized users attempting to read dmesg output
• Implement audit logging on kernel log file access using auditd rules
• Review system logs for hex dump patterns that may indicate password exposure
• Deploy endpoint detection to identify credential harvesting behavior from log files

Monitoring Recommendations

• Enable enhanced logging on Dell systems to track password change operations
• Configure alerts for unusual kernel log access patterns
• Implement log rotation and secure deletion to minimize exposure window
• Use SentinelOne Singularity to monitor for suspicious local file access patterns targeting kernel logs

How to Mitigate CVE-2026-23370

Immediate Actions Required

• Update the Linux kernel to a patched version that removes the hex dump from set_new_password()
• Review kernel logs for any existing password exposure and rotate potentially compromised credentials
• Restrict access to kernel debug output and system logs to authorized administrators only
• Consider temporarily disabling Dell WMI Sysman functionality if password changes are not required

Patch Information

The Linux kernel maintainers have addressed this vulnerability by removing the hex dump functionality from the set_new_password() function. Multiple kernel commits have been released to fix this issue across different stable kernel branches:

• Kernel Commit 0e6115c2f2fa
• Kernel Commit 411ba3cd837f
• Kernel Commit 5de34126fb2e
• Kernel Commit d1a196e0a6dc
• Kernel Commit d78e74adc5cf
• Kernel Commit d9e785bd62d2

System administrators should apply the appropriate patch for their kernel version or upgrade to a kernel release containing the fix.

Workarounds

• Restrict read access to /var/log/kern.log and similar kernel log files to root only
• Disable the dell-wmi-sysman module if not required using modprobe -r dell-wmi-sysman
• Implement strict auditd rules to monitor and alert on kernel log access
• Clear existing kernel logs that may contain exposed password data after securing the system

# Configuration example
# Restrict kernel log access permissions
chmod 600 /var/log/kern.log
chmod 600 /var/log/dmesg

# Disable dell-wmi-sysman module if not needed
echo "blacklist dell-wmi-sysman" >> /etc/modprobe.d/blacklist-dell.conf
modprobe -r dell-wmi-sysman

# Add audit rule to monitor kernel log access
auditctl -w /var/log/kern.log -p r -k kernel_log_access