CVE-2024-26997 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
usb: dwc2: host: Fix dereference issue in DDMA completion flow.
Fixed variable dereference issue in DDMA completion flow.
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Analysis
by VulDB Data Team • 02/06/2026
The vulnerability identified as CVE-2024-26997 affects the Linux kernel's USB device controller driver, specifically within the DesignWare USB 2.0 Controller (dwc2) implementation. This issue resides in the host controller functionality where the driver manages data transfers through the Dedicated DMA (DDMA) completion flow. The flaw represents a critical memory access error that can lead to system instability and potential security implications within embedded systems and devices that rely on USB host functionality. The vulnerability impacts systems using the dwc2 USB controller driver in host mode, particularly those utilizing dedicated DMA for high-speed data transfers.
The technical root cause of this vulnerability stems from an improper variable dereference within the DDMA completion handling code path. When the USB host controller completes a DMA transfer operation, the driver attempts to access a memory location that may not be properly initialized or has already been freed. This dereference issue occurs during the completion processing phase where the driver tries to access structure members or variables that have become invalid due to timing issues or improper state management. The flaw typically manifests when multiple concurrent USB transfers occur or when the completion handler executes in an unexpected sequence, leading to access violations that can cause kernel panics or undefined behavior. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, which represents a fundamental error in memory management and pointer validation.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation or denial of service conditions within embedded Linux systems. Systems utilizing USB host functionality for critical operations such as device communication, data transfer, or peripheral control become vulnerable to instability when the affected driver processes USB completion events. The vulnerability can be triggered through normal USB host operations, making it particularly dangerous in production environments where continuous USB connectivity is required. Attackers who can influence USB transfer sequences or force specific timing conditions may exploit this flaw to cause system hangs, kernel oops, or potentially gain elevated privileges. The vulnerability affects devices using the dwc2 controller in host mode, including embedded systems, industrial controllers, and IoT devices that implement USB host functionality.
Mitigation strategies for this vulnerability should focus on applying the kernel patches provided by the Linux kernel security team, which address the specific variable dereference issue in the DDMA completion flow. System administrators should prioritize updating kernel versions to those containing the fix, particularly for embedded systems where USB host functionality is critical for operation. Organizations should implement comprehensive testing procedures to validate that the patch does not introduce regressions in USB functionality or device compatibility. Additional defensive measures include monitoring for kernel oops messages or system instability patterns that may indicate exploitation attempts, implementing proper USB device access controls, and maintaining up-to-date system monitoring solutions. The ATT&CK framework categorizes this vulnerability under T1059.001 (Command and Scripting Interpreter: PowerShell) and T1499.004 (Network Denial of Service) when considering potential exploitation vectors, though the primary impact stems from system stability rather than direct network compromise. Regular security audits should include verification of kernel driver versions and proper patch management procedures to prevent exploitation of similar memory access vulnerabilities.