CVE-2026-23132 Overview
A vulnerability has been identified in the Linux kernel's DRM (Direct Rendering Manager) bridge subsystem, specifically in the Synopsys DesignWare DisplayPort (dw-dp) driver. The dw_dp_bind() function contains multiple error handling flaws that can lead to resource leaks and improper error propagation during device initialization.
Critical Impact
Improper error handling in the dw_dp_bind() function can result in resource leaks, continued execution after failure conditions, and incorrect error code propagation, potentially leading to system instability or denial of service conditions.
Affected Products
- Linux Kernel (versions with vulnerable drm/bridge/synopsys/dw-dp driver)
- Systems utilizing Synopsys DesignWare DisplayPort bridge hardware
Discovery Timeline
- 2026-02-14 - CVE CVE-2026-23132 published to NVD
- 2026-02-18 - Last updated in NVD database
Technical Details for CVE-2026-23132
Vulnerability Analysis
The vulnerability exists in the dw_dp_bind() function within the Linux kernel's DRM bridge subsystem for Synopsys DesignWare DisplayPort hardware. This function is responsible for binding the DisplayPort bridge device during system initialization. The implementation contains three distinct error handling defects that compromise the reliability and security of the driver.
The first issue involves a missing return statement after a drm_bridge_attach() failure. When this function fails, execution continues inappropriately rather than returning an error code, potentially leading to undefined behavior as subsequent code operates on improperly initialized structures.
The second issue is a resource leak affecting the AUX channel registration. The drm_dp_aux_register() function is not a devm (device-managed) function, meaning drm_dp_aux_unregister() must be explicitly called on all error paths following successful AUX registration. The original code failed to properly clean up this resource when errors occurred in subsequent operations including drm_bridge_attach(), phy_init(), devm_add_action_or_reset(), platform_get_irq(), and devm_request_threaded_irq().
The third issue involves incorrect error code handling from platform_get_irq(). This function returns either a valid IRQ number or a negative error code, but the error path was incorrectly using ERR_PTR(ret) instead of ERR_PTR(dp->irq), resulting in incorrect error propagation to callers.
Root Cause
The root cause is improper implementation of error handling paths in the dw_dp_bind() function. The code lacked a unified cleanup mechanism using goto labels, which is the standard pattern in Linux kernel development for handling multiple cleanup steps. The absence of this pattern led to incomplete resource cleanup, missing error returns, and incorrect error code propagation.
Attack Vector
This vulnerability has a local attack vector requiring access to a system with the affected Synopsys DesignWare DisplayPort hardware. Exploitation would likely involve triggering error conditions during device initialization, potentially through:
- Hardware fault injection during system boot
- Manipulating device tree configurations
- Triggering resource allocation failures during driver binding
The vulnerability primarily presents a denial of service risk through resource exhaustion from repeated memory leaks, or system instability from operating on improperly initialized data structures.
Detection Methods for CVE-2026-23132
Indicators of Compromise
- Unexpected memory consumption growth in kernel space over time
- Kernel warning messages related to DRM bridge initialization failures
- System instability or crashes during DisplayPort device enumeration
- Resource exhaustion warnings in kernel logs related to the dw-dp driver
Detection Strategies
- Monitor kernel logs for error messages from the drm/bridge/synopsys/dw-dp driver
- Implement kernel memory leak detection tools such as kmemleak to identify unreleased resources
- Track system memory usage patterns for gradual increases indicating kernel memory leaks
- Review dmesg output during system boot for DisplayPort bridge initialization errors
Monitoring Recommendations
- Configure centralized logging to capture kernel messages related to DRM subsystem errors
- Implement automated alerting for unusual memory consumption patterns in kernel space
- Deploy SentinelOne Singularity platform for real-time kernel-level monitoring and anomaly detection
- Regularly audit systems with Synopsys DesignWare DisplayPort hardware for signs of driver instability
How to Mitigate CVE-2026-23132
Immediate Actions Required
- Update the Linux kernel to a patched version containing the fix commits
- Review systems with Synopsys DesignWare DisplayPort hardware for signs of resource leaks
- Monitor kernel memory usage on affected systems until patches can be applied
- Consider disabling the dw-dp driver module on non-essential systems if the hardware is not required
Patch Information
The vulnerability has been addressed in the Linux kernel through commits that implement proper goto-based error handling in the dw_dp_bind() function. The fix ensures:
- Proper return after drm_bridge_attach() failure
- Consistent cleanup of drm_dp_aux_register() resources on all error paths
- Correct error code propagation from platform_get_irq()
The patches are available through the following kernel git commits:
Workarounds
- Blacklist the dw-dp kernel module on systems where DisplayPort functionality is not required
- Limit physical access to systems to prevent hardware-based exploitation attempts
- Implement system monitoring to detect and respond to resource leak conditions
- Consider using alternative display output methods if the affected hardware can be bypassed
# Blacklist the dw-dp module if not required
echo "blacklist dw-dp" >> /etc/modprobe.d/blacklist.conf
# Update initramfs to apply the blacklist
update-initramfs -u
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
