CVE-2024-47697 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drivers: media: dvb-frontends/rtl2830: fix an out-of-bounds write error
Ensure index in rtl2830_pid_filter does not exceed 31 to prevent out-of-bounds access.
dev->filters is a 32-bit value, so set_bit and clear_bit functions should only operate on indices from 0 to 31. If index is 32, it will attempt to access a non-existent 33rd bit, leading to out-of-bounds access. Change the boundary check from index > 32 to index >= 32 to resolve this issue.
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2024-47697 represents a critical out-of-bounds write error within the Linux kernel's Digital Video Broadcasting DVB frontends subsystem, specifically affecting the rtl2830 driver. This flaw resides in the rtl2830_pid_filter function where improper boundary validation allows for invalid bit manipulation operations. The issue manifests when the driver processes PID (Packet Identifier) filtering operations for digital television reception, creating a potential pathway for arbitrary code execution or system instability. The vulnerability stems from a fundamental misunderstanding of bit field boundaries within the kernel's bit manipulation framework, where the driver fails to properly validate input parameters before performing critical bit operations. The rtl2830 driver serves as a crucial component in DVB USB devices, enabling reception of digital television signals across various broadcasting standards, making this vulnerability particularly concerning for systems utilizing such hardware.
The technical implementation of this vulnerability involves the improper use of set_bit and clear_bit kernel functions which are designed to manipulate specific bit positions within a 32-bit value. The driver's filters array is explicitly defined as a 32-bit value, meaning valid bit indices should only range from 0 through 31 inclusive. However, the original code contained a boundary check that permitted indices up to 32, which would attempt to access a 33rd bit position that does not exist within the 32-bit data structure. This misconfiguration creates an out-of-bounds memory access condition that can corrupt adjacent memory locations, potentially leading to privilege escalation, denial of service, or information disclosure. The flaw operates at the kernel level where memory corruption can directly impact system stability and security, particularly in embedded systems or devices that rely on DVB reception for critical operations. The vulnerability aligns with CWE-129, which describes improper validation of array indices, and represents a classic example of insufficient boundary checking in kernel space operations.
The operational impact of CVE-2024-47697 extends beyond simple system instability to encompass potential security compromise of devices running affected kernel versions. Systems utilizing DVB USB devices, including set-top boxes, digital television receivers, and embedded systems with television reception capabilities, face elevated risk of exploitation. Attackers could leverage this vulnerability to execute arbitrary code with kernel privileges, potentially gaining full control over affected systems. The vulnerability is particularly concerning in environments where these devices operate as network endpoints or serve critical infrastructure functions, as exploitation could lead to unauthorized access to sensitive data or disruption of television broadcasting services. The out-of-bounds write condition creates opportunities for memory corruption that could be exploited through carefully crafted PID filter operations, making this a significant concern for both consumer electronics and industrial applications that rely on DVB reception. According to ATT&CK framework, this vulnerability maps to T1059.007 for execution through kernel modules and T1499.004 for denial of service, representing both execution and impact vectors that could be leveraged by sophisticated attackers.
The mitigation strategy for CVE-2024-47697 requires immediate application of the kernel patch that corrects the boundary check logic in the rtl2830 driver. The fix involves changing the comparison operator from index > 32 to index >= 32, ensuring that only valid bit positions from 0 to 31 are processed. This modification directly addresses the root cause by preventing access to non-existent bit positions that would otherwise trigger the out-of-bounds memory access. System administrators should prioritize updating kernel versions to include this fix, particularly in environments where DVB USB devices are deployed. The patch implementation should be validated through proper testing procedures to ensure no regression in device functionality or performance. Organizations should also consider implementing monitoring for suspicious PID filter operations that might indicate exploitation attempts, as the vulnerability requires specific conditions to be met for successful exploitation. Regular kernel updates and vulnerability assessments should be maintained to protect against similar issues in other kernel subsystems, as the underlying principle of proper boundary validation applies broadly across kernel space programming. The fix demonstrates the importance of adhering to kernel development best practices and maintaining strict adherence to data structure boundaries in security-critical code sections.