CVE-2024-49928 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
wifi: rtw89: avoid reading out of bounds when loading TX power FW elements
Because the loop-expression will do one more time before getting false from cond-expression, the original code copied one more entry size beyond valid region.
Fix it by moving the entry copy to loop-body.
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Analysis
by VulDB Data Team • 03/17/2026
The vulnerability CVE-2024-49928 affects the Linux kernel's wireless subsystem, specifically within the rtw89 driver that manages Realtek wireless network adapters. This issue represents a classic buffer overread condition that occurs during the firmware loading process for transmission power settings. The flaw manifests when the driver attempts to process firmware elements containing TX power information, creating a scenario where memory access extends beyond the allocated bounds of valid data structures. Such out-of-bounds reads can lead to unpredictable behavior including system crashes, data corruption, or potential exploitation for privilege escalation attacks.
The technical root cause stems from improper loop boundary handling within the firmware element processing code. The original implementation employs a loop structure where the conditional expression evaluates to true one additional time before terminating, causing the code to copy data beyond the legitimate memory boundaries of the firmware elements. This particular pattern violates fundamental memory safety principles and demonstrates a classic off-by-one error in loop management. The vulnerability is categorized under CWE-129 as an insufficient bounds checking, specifically manifesting as an improper access to memory beyond the allocated buffer. The rtw89 driver's firmware loading mechanism fails to properly validate array indices against the actual size of the firmware element structure, leading to memory corruption during the transmission power table initialization process.
Operationally, this vulnerability poses significant risks to systems running affected Linux kernel versions, particularly those utilizing Realtek wireless network adapters. The out-of-bounds read could result in system instability, causing unexpected kernel panics or wireless adapter malfunctions that might require system reboots. In more severe scenarios, if an attacker can control the firmware content or manipulate the conditions leading to this code path, the vulnerability could potentially be exploited to execute arbitrary code within kernel space. The attack surface is primarily limited to systems where the rtw89 driver is actively loaded and processing firmware elements, which typically includes laptops, desktops, and servers with Realtek wireless networking capabilities. The vulnerability aligns with ATT&CK technique T1068 by potentially enabling local privilege escalation through kernel memory corruption, and T1547 by targeting system-level components that could be leveraged for persistent access.
Mitigation strategies should prioritize immediate patch application from kernel vendors, as the fix involves a straightforward code modification that relocates the entry copying operation within the loop body to prevent the additional memory access. System administrators should ensure all Linux systems with Realtek wireless adapters are updated to kernel versions containing the patched rtw89 driver implementation. Additional defensive measures include monitoring for unusual system behavior or kernel panic messages that might indicate exploitation attempts. The fix demonstrates proper defensive programming practices by ensuring loop boundaries are correctly managed and memory access is strictly confined to valid data regions. Organizations should also consider implementing firmware integrity checks and monitoring for unauthorized firmware modifications that could potentially trigger this vulnerability through malicious firmware injection scenarios.