CVE-2022-48873 in Linux
Summary
by MITRE • 08/21/2024
In the Linux kernel, the following vulnerability has been resolved:
misc: fastrpc: Don't remove map on creater_process and device_release
Do not remove the map from the list on error path in fastrpc_init_create_process, instead call fastrpc_map_put, to avoid use-after-free. Do not remove it on fastrpc_device_release either, call fastrpc_map_put instead.
The fastrpc_free_map is the only proper place to remove the map. This is called only after the reference count is 0.
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Analysis
by VulDB Data Team • 02/17/2026
The vulnerability identified as CVE-2022-48873 resides within the Linux kernel's fastrpc subsystem, specifically affecting the management of memory mappings during process creation and device release operations. This issue represents a classic use-after-free vulnerability that can potentially lead to system instability or privilege escalation. The flaw manifests when the kernel attempts to manage memory mapping structures during device initialization and cleanup phases, where improper reference counting and resource management create opportunities for memory corruption.
The technical root cause stems from incorrect handling of memory mapping references within the fastrpc_init_create_process function and the fastrpc_device_release function. During error paths in process creation, the code removes mapping entries from lists before properly releasing references, creating a scenario where subsequent access to these freed structures can occur. Similarly, during device release operations, the same improper reference management pattern exists. This violates fundamental memory safety principles and creates conditions where attackers could potentially exploit the timing window between reference counting and actual resource deallocation. The vulnerability is categorized under CWE-415 as an improper handling of memory allocation and deallocation, specifically manifesting as a use-after-free condition.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling privilege escalation attacks within the kernel context. When the fastrpc_map_put function is not properly called in error paths, it results in reference counts not being decremented correctly, leading to premature deallocation of memory structures. This creates a window where malicious actors could manipulate the system into accessing freed memory regions, potentially allowing for arbitrary code execution with kernel privileges. The vulnerability affects systems utilizing the fastrpc subsystem, which is commonly found in mobile and embedded systems that require high-performance inter-process communication mechanisms. The impact is particularly severe because it occurs within kernel space, where memory corruption can lead to complete system compromise.
Mitigation strategies for CVE-2022-48873 focus on correcting the reference counting logic within the fastrpc subsystem. The recommended approach involves ensuring that fastrpc_map_put is called consistently in all code paths, including error conditions, rather than removing mappings from lists directly. This aligns with the ATT&CK framework's defense evasion techniques, where proper resource management prevents exploitation of memory corruption vulnerabilities. System administrators should prioritize applying kernel updates that contain the patched implementation, which properly centralizes map removal operations in the fastrpc_free_map function. Additionally, monitoring systems for unusual memory access patterns and implementing kernel hardening measures such as stack canaries and address space layout randomization can provide additional protection layers. The fix ensures that memory mappings are only removed when the reference count reaches zero, preventing the use-after-free conditions that could be exploited by attackers to gain elevated privileges within the kernel space.