CVE-2026-23337 Overview
A memory leak vulnerability has been identified in the Linux kernel's pinctrl subsystem, specifically within the pinconf_generic_parse_dt_config() function. When the parse_dt_cfg() function fails during device tree configuration parsing, the code returns directly without executing the necessary cleanup logic, resulting in a memory leak of the cfg buffer.
Critical Impact
This memory leak vulnerability could lead to kernel memory exhaustion over time, potentially causing system instability or denial of service conditions on affected Linux systems.
Affected Products
- Linux kernel (pinctrl subsystem)
- Systems using pinconf-generic device tree configuration
- Embedded Linux platforms utilizing pin controller drivers
Discovery Timeline
- 2026-03-25 - CVE CVE-2026-23337 published to NVD
- 2026-03-25 - Last updated in NVD database
Technical Details for CVE-2026-23337
Vulnerability Analysis
The vulnerability exists in the pinconf_generic_parse_dt_config() function within the pinctrl subsystem's generic configuration parser. During the parsing of device tree configurations, a buffer (cfg) is allocated to hold the parsed configuration data. When a subsequent call to parse_dt_cfg() fails, the function returns immediately with an error code, bypassing the cleanup path that would normally free the allocated memory.
This is a classic example of an error handling path that fails to properly release allocated resources. The memory leak accumulates each time the parsing function is invoked and fails, leading to gradual kernel memory consumption that cannot be reclaimed until system reboot.
Root Cause
The root cause is an improper error handling path in pinconf_generic_parse_dt_config(). The function allocates a cfg buffer early in execution but does not properly jump to the cleanup label when parse_dt_cfg() returns an error. Instead of using a goto out statement to ensure kfree(cfg) is called, the code performs a direct return, leaving the allocated memory orphaned.
Attack Vector
While the attack vector is classified as unknown, the vulnerability is triggered through device tree configuration parsing operations. An attacker with the ability to influence device tree configurations or trigger repeated parsing failures could potentially cause memory exhaustion. However, exploitation typically requires local access or specific conditions that cause the parse_dt_cfg() function to fail repeatedly.
The vulnerability mechanism involves error path handling in kernel memory management. When parse_dt_cfg() fails, the function should transfer control to the out label to execute cleanup code, but instead returns directly, leaving the cfg buffer allocated without any reference to free it later. For technical implementation details, see the kernel Git commit.
Detection Methods for CVE-2026-23337
Indicators of Compromise
- Gradual increase in kernel memory usage without corresponding application memory growth
- System logs showing repeated pinctrl configuration parsing failures
- Memory allocation patterns in /proc/slabinfo showing unusual pinctrl-related allocations
Detection Strategies
- Monitor kernel memory allocation trends using tools like slabtop or /proc/meminfo
- Enable kernel memory debugging options (CONFIG_DEBUG_KMEMLEAK) to detect unreferenced memory allocations
- Review system logs for pinctrl subsystem error messages indicating configuration parsing failures
Monitoring Recommendations
- Implement continuous monitoring of kernel memory consumption on affected systems
- Set up alerts for unusual memory growth patterns that may indicate memory leak exploitation
- Deploy kernel tracing tools to identify repeated failures in the pinconf subsystem
How to Mitigate CVE-2026-23337
Immediate Actions Required
- Update to a patched Linux kernel version that includes the fix for this vulnerability
- Monitor systems for signs of memory exhaustion until patches can be applied
- Prioritize patching on systems that frequently parse device tree configurations
Patch Information
The Linux kernel development team has released patches to address this vulnerability. The fix modifies the error handling path in pinconf_generic_parse_dt_config() to jump to the out label on failure instead of returning directly, ensuring that kfree(cfg) is properly called before the function returns.
Relevant patches are available at:
Workarounds
- No specific workarounds are available; applying the kernel patch is the recommended remediation
- Systems experiencing memory pressure can be temporarily mitigated by scheduling regular reboots
- Limit access to device tree configuration interfaces where possible to reduce exposure
# Check current kernel version and update to patched version
uname -r
# Update kernel using your distribution's package manager
# For Debian/Ubuntu:
apt update && apt upgrade linux-image-generic
# For RHEL/CentOS:
yum update kernel
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
