CVE-2024-50289 in Linux
Summary
by MITRE • 11/19/2024
In the Linux kernel, the following vulnerability has been resolved:
media: av7110: fix a spectre vulnerability
As warned by smatch: drivers/staging/media/av7110/av7110_ca.c:270 dvb_ca_ioctl() warn: potential spectre issue 'av7110->ci_slot' [w] (local cap)
There is a spectre-related vulnerability at the code. Fix it.
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Analysis
by VulDB Data Team • 10/08/2025
The vulnerability CVE-2024-50289 addresses a speculative execution side-channel issue within the Linux kernel's media subsystem, specifically affecting the av7110 driver used for DVB (Digital Video Broadcasting) hardware support. This particular vulnerability resides in the dvb_ca_ioctl function where the kernel's spectre warning tool smatch has identified a potential security flaw related to the av7110->ci_slot variable access pattern. The issue manifests as a speculative execution vulnerability that could potentially allow an attacker to extract sensitive information through side-channel attacks.
The technical flaw occurs within the av7110_ca.c file at line 270 where the dvb_ca_ioctl function handles CA (Conditional Access) ioctl operations for the av7110 device. The spectre vulnerability arises from how the kernel accesses the ci_slot member of the av7110 structure during conditional operations. When the kernel performs speculative execution on code paths that depend on user-controlled input or variables, it can lead to information leakage through cache timing attacks or similar side-channel techniques. The specific warning indicates that the local variable av7110->ci_slot is being accessed in a way that creates a potential speculative execution hazard, where the processor's speculative execution might incorrectly predict and execute code paths that should be protected from unauthorized access.
This vulnerability impacts systems running Linux kernels with the av7110 driver enabled, particularly those supporting DVB hardware such as satellite receivers and digital television tuners. The operational impact of this spectre vulnerability could allow attackers with local access or those exploiting other vulnerabilities to potentially extract sensitive cryptographic keys or other confidential data from the kernel's memory space. The attack vector typically requires an attacker to have some level of access to the system to leverage the speculative execution flaw, though the exact attack surface depends on the specific implementation details and surrounding security controls. Systems handling sensitive content or operating in environments where information leakage could compromise security would be particularly at risk.
The fix for this vulnerability involves implementing proper bounds checking and input validation for the ci_slot variable access, ensuring that speculative execution paths cannot be manipulated to leak information. This typically requires adding memory barriers or other mitigations that prevent the processor from speculatively executing code paths that could lead to information disclosure. The solution aligns with established security practices for addressing spectre vulnerabilities as outlined in the CWE-119 category which covers memory safety issues and the ATT&CK framework's mitigation strategies for speculative execution attacks. The kernel maintainers have implemented appropriate code changes to ensure that the ci_slot variable access pattern no longer creates exploitable speculative execution hazards, thereby protecting against potential information leakage attacks that could compromise the security of the DVB subsystem and the broader system.
This vulnerability demonstrates the ongoing importance of security auditing in kernel code, particularly for drivers handling sensitive operations like conditional access for digital television content. The fix represents a standard approach to addressing spectre vulnerabilities in kernel space, following established patterns for mitigating speculative execution side-channels that have become increasingly relevant as modern processors implement aggressive optimization techniques. The resolution ensures that the av7110 driver maintains proper security boundaries while continuing to support its intended functionality for DVB hardware devices.