CVE-2022-50745 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
staging: media: tegra-video: fix device_node use after free
At probe time this code path is followed:
* tegra_csi_init * tegra_csi_channels_alloc * for_each_child_of_node(node, channel) -- iterates over channels * automatically gets 'channel' * tegra_csi_channel_alloc() * saves into chan->of_node a pointer to the channel OF node * automatically gets and puts 'channel' * now the node saved in chan->of_node has refcount 0, can disappear * tegra_csi_channels_init * iterates over channels * tegra_csi_channel_init -- uses chan->of_node
After that, chan->of_node keeps storing the node until the device is removed.
of_node_get() the node and of_node_put() it during teardown to avoid any risk.
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Analysis
by VulDB Data Team • 04/21/2026
The vulnerability described in CVE-2022-50745 represents a critical use-after-free condition within the Linux kernel's Tegra video subsystem, specifically affecting the staging media driver for Tegra platforms. This flaw exists in the device tree node management logic during the initialization phase of CSI (Camera Serial Interface) channels, creating a scenario where a device node pointer becomes invalid while still being referenced by the driver code. The issue manifests in the tegra_csi_channels_alloc function where the driver iterates through child nodes of a parent device node to allocate CSI channels, with each channel's device tree node being stored in a channel structure for later use. The root cause stems from improper reference counting of device tree nodes, where the driver saves a pointer to a device tree node without incrementing its reference count, leading to a situation where the node can be freed while still being referenced by the channel structure.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates a potential attack surface for privilege escalation and system instability within embedded Linux systems that utilize Tegra hardware platforms. The flaw occurs during the device probe sequence when the driver attempts to initialize CSI channels, with the specific code path leading to the problematic state through multiple function calls including tegra_csi_init, tegra_csi_channels_alloc, and ultimately tegra_csi_channels_init. The vulnerability is classified under CWE-416 as Use After Free, which represents a well-known category of memory safety issues that can lead to arbitrary code execution when attackers can control the freed memory location. The attack vector becomes particularly concerning in embedded systems where the kernel runs with elevated privileges and where device tree manipulation might be possible through various attack surfaces.
The technical implementation of this vulnerability demonstrates a classic reference counting error in device tree node management, where the driver fails to properly maintain the lifecycle of device tree nodes through the use of of_node_get() and of_node_put() functions. During the allocation phase, each channel's device tree node is stored in chan->of_node without incrementing the reference count, which means that when the parent node iteration completes and subsequent cleanup operations occur, the referenced node may have already been freed by the device tree subsystem. This creates a dangling pointer scenario where later access to chan->of_node during channel initialization attempts to reference memory that has been deallocated, potentially leading to kernel crashes, data corruption, or more severe exploitation scenarios. The fix implemented addresses this by ensuring proper reference counting through explicit calls to of_node_get() during allocation and of_node_put() during cleanup, thereby preventing the premature deallocation of device tree nodes while they remain in use.
The mitigation strategy for this vulnerability requires kernel updates that implement proper reference counting mechanisms for device tree nodes within the Tegra video driver, specifically addressing the missing of_node_get() calls during channel allocation and the corresponding of_node_put() operations during device teardown. Organizations deploying Linux-based systems on Tegra hardware platforms must prioritize patching this vulnerability, as it affects the stability and security of embedded systems including automotive infotainment systems, industrial control devices, and mobile platforms. The fix aligns with best practices for device tree node management as recommended by the Linux kernel development community and follows the ATT&CK framework's T1068 technique for exploiting local privilege escalation through kernel vulnerabilities. System administrators should monitor for kernel updates from their respective distributions and apply patches promptly, as this vulnerability could potentially be exploited by malicious actors to gain unauthorized access to embedded systems or cause denial of service conditions in production environments.