CVE-2026-23132 Overview
CVE-2026-23132 affects the Linux kernel drm/bridge/synopsys/dw-dp DisplayPort driver. The flaw resides in the dw_dp_bind() function, where multiple error-handling paths fail to release resources correctly. A missing return statement after drm_bridge_attach() failure causes execution to continue after an error, and successful drm_dp_aux_register() calls are not paired with drm_dp_aux_unregister() on subsequent failure paths. The error path also incorrectly returns ERR_PTR(ret) instead of ERR_PTR(dp->irq) after platform_get_irq() failure. The defect impacts Linux kernel 6.19 release candidates and earlier supported branches.
Critical Impact
A local user can trigger driver bind failures that produce kernel resource leaks and inconsistent state, leading to high availability impact on affected systems.
Affected Products
- Linux kernel 6.19-rc1 through 6.19-rc6
- Linux kernel branches containing the drm/bridge/synopsys/dw-dp driver
- Systems using Synopsys DesignWare DisplayPort bridge hardware
Discovery Timeline
- 2026-02-14 - CVE-2026-23132 published to the National Vulnerability Database
- 2026-03-17 - Last updated in the NVD database
Technical Details for CVE-2026-23132
Vulnerability Analysis
The defect lives in the dw_dp_bind() initialization routine of the Synopsys DesignWare DisplayPort (DP) bridge driver under drivers/gpu/drm/bridge/synopsys/dw-dp.c. The function performs a sequence of setup operations including drm_bridge_attach(), drm_dp_aux_register(), phy_init(), devm_add_action_or_reset(), platform_get_irq(), and devm_request_threaded_irq(). Several of these calls can fail, but the original implementation handled errors inconsistently. As a result, a failed bind operation leaves AUX channel registration active, IRQ resources unreleased, and an incorrect error code propagated upward.
Root Cause
Three distinct defects compose the issue. First, after drm_bridge_attach() returned an error, the function lacked a return statement and continued execution against an invalid state. Second, drm_dp_aux_register() is not a devm_ managed function, so it requires an explicit drm_dp_aux_unregister() call on every subsequent failure path; that call was missing. Third, on platform_get_irq() failure the routine returned ERR_PTR(ret) instead of ERR_PTR(dp->irq), masking the real error value. The fix consolidates cleanup behind a goto label to enforce consistent unwinding.
Attack Vector
Exploitation requires local access with low privileges and no user interaction. An attacker who can influence driver binding, such as through device hot-plug events or repeated module load operations on hardware with the Synopsys DP bridge, can trigger error paths that leak kernel resources or destabilize the DRM subsystem. The flaw does not expose confidentiality or integrity but produces a high availability impact, including potential denial of service through resource exhaustion or kernel state inconsistencies.
No public proof-of-concept code or exploit is available for CVE-2026-23132. The kernel maintainers describe the resolution in the commit messages referenced by Kernel.org Patch Update and Kernel.org Commit Information.
Detection Methods for CVE-2026-23132
Indicators of Compromise
- Repeated dw_dp_bind failure messages in dmesg or journalctl output on systems with Synopsys DesignWare DP bridge hardware
- Kernel warnings referencing drm_dp_aux registration without matching unregistration
- Unexpected IRQ allocation failures on the DisplayPort bridge device after module reload events
Detection Strategies
- Audit installed kernel versions against the patched commits 1a0f69e3c284 and 569ed6a73e92 to identify exposed hosts
- Monitor for abnormal DRM subsystem state transitions during graphics driver initialization or hot-plug events
- Track module load and unload activity for dw-dp and related Synopsys DRM bridge modules
Monitoring Recommendations
- Centralize kernel logs and alert on recurring DRM bridge bind errors from affected hosts
- Track device-driver bind and unbind events through udev and sysfs auditing
- Correlate IRQ allocation anomalies with display subsystem activity to surface attempted abuse
How to Mitigate CVE-2026-23132
Immediate Actions Required
- Inventory Linux hosts running kernel 6.19-rc1 through 6.19-rc6 that use the Synopsys DesignWare DisplayPort bridge
- Apply the upstream stable kernel updates containing commits 1a0f69e3c284 and 569ed6a73e92
- Restrict local access on systems pending patch deployment, particularly for users able to trigger driver bind events
Patch Information
The Linux kernel maintainers resolved the issue by introducing a goto-based cleanup label inside dw_dp_bind(), ensuring drm_dp_aux_unregister() runs on every failure path after AUX registration succeeds, adding the missing return after drm_bridge_attach() failure, and correcting the platform_get_irq() error return to use ERR_PTR(dp->irq). The fix is available through the Kernel.org Patch Update and the Kernel.org Commit Information.
Workarounds
- Blacklist the dw-dp kernel module on hosts that do not require DisplayPort bridge functionality
- Limit CAP_SYS_ADMIN and device-management capabilities so unprivileged users cannot drive bind or unbind operations
- Disable hot-plug handling for the affected bridge until a patched kernel is deployed
# Configuration example: prevent the affected module from loading
echo 'blacklist dw-dp' | sudo tee /etc/modprobe.d/blacklist-dw-dp.conf
sudo update-initramfs -u
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
