CVE-2024-36900 in Linux
Summary
by MITRE • 05/30/2024
In the Linux kernel, the following vulnerability has been resolved:
net: hns3: fix kernel crash when devlink reload during initialization
The devlink reload process will access the hardware resources, but the register operation is done before the hardware is initialized. So, processing the devlink reload during initialization may lead to kernel crash.
This patch fixes this by registering the devlink after hardware initialization.
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Analysis
by VulDB Data Team • 09/30/2025
The vulnerability CVE-2024-36900 affects the Linux kernel's hns3 network driver implementation and represents a critical race condition during device initialization. This issue occurs within the Hardware Networking Subsystem where the devlink reload functionality attempts to access hardware resources before the underlying hardware has been properly initialized. The problem manifests as a kernel crash when the devlink reload process is executed during the device initialization phase, creating a scenario where memory access violations or hardware register operations occur against uninitialized hardware components. The root cause lies in the improper sequencing of initialization operations where hardware register access is performed prior to the completion of hardware initialization routines, leading to unpredictable system behavior and potential denial of service conditions.
The technical flaw stems from a fundamental timing issue in the driver's initialization sequence where the devlink subsystem registration occurs before hardware initialization is complete. This creates a window of opportunity for the devlink reload mechanism to attempt register operations on hardware that has not yet been properly configured or powered on. When the devlink reload process executes during this initialization window, it attempts to access memory-mapped registers or hardware control interfaces that are either unmapped, uninitialized, or in an undefined state, resulting in kernel panics or system crashes. This type of vulnerability falls under CWE-362, which describes a race condition where operations on shared resources are not properly synchronized, and specifically relates to improper initialization sequences that lead to memory access violations.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise network availability and system stability in environments where network hardware is frequently reinitialized or reloaded. Network administrators and system operators may experience unexpected downtime when network devices are being initialized or reloaded, particularly in high-availability environments where network reliability is critical. The vulnerability affects systems using HNS3 (Huawei Networking Subsystem 3) network adapters and could be exploited in scenarios where automated network management systems trigger devlink reload operations during system boot processes or hardware reconfiguration events. This creates a significant risk for data center environments, cloud infrastructure providers, and enterprise networks that rely on stable network device operations and may result in cascading failures when network subsystems become unavailable.
The fix for CVE-2024-36900 implements a proper initialization sequencing by deferring the devlink subsystem registration until after hardware initialization is complete. This approach follows established best practices for device driver development where hardware resources must be fully initialized and validated before any access operations are permitted. The patch ensures that register operations and hardware resource access occur only after the device is in a stable operational state, preventing the race condition that previously led to kernel crashes. From an ATT&CK perspective, this vulnerability and its remediation relate to privilege escalation and system stability manipulation techniques that could be leveraged by attackers to disrupt network services or cause denial of service conditions. Organizations should prioritize applying this patch to maintain network stability and prevent potential exploitation scenarios that could lead to unauthorized service disruption or system compromise. The mitigation strategy aligns with the principle of least privilege and proper resource initialization, ensuring that all subsystems are properly established before they attempt to access critical hardware resources.