CVE-2024-49853 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
firmware: arm_scmi: Fix double free in OPTEE transport
Channels can be shared between protocols, avoid freeing the same channel descriptors twice when unloading the stack.
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2024-49853 resides within the Linux kernel's firmware subsystem, specifically affecting the arm_scmi driver implementation. This issue manifests as a double free condition that occurs during the cleanup process of OPTEE transport channel descriptors. The arm_scmi driver facilitates communication between the operating system and system management controllers through the System Management Controller Interface protocol, which is commonly used in ARM-based embedded systems and mobile devices. The vulnerability is particularly significant because it affects the fundamental firmware communication mechanisms that enable system management and power control functions.
The technical flaw stems from improper memory management within the driver's unloading procedure where channel descriptors that may be shared across multiple protocols are being freed more than once. When the kernel module is unloaded, the code attempts to release memory resources associated with communication channels, but fails to properly track whether a particular channel descriptor has already been freed during the cleanup of shared resources. This results in a classic double free vulnerability where the same memory block is deallocated twice, potentially leading to memory corruption and undefined behavior. The issue is particularly dangerous because it occurs in kernel space where such memory corruption can lead to privilege escalation or system instability.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a potential pathway for attackers to exploit kernel memory management flaws. The double free condition could be leveraged to execute arbitrary code with kernel privileges, effectively bypassing kernel address space layout randomization and other security mitigations. The vulnerability affects systems that utilize the OPTEE transport mechanism for secure communication between the kernel and trusted execution environments, which are commonly found in mobile devices, embedded systems, and IoT devices where secure firmware communication is essential. According to CWE classification, this vulnerability maps to CWE-415: Double Free, which is a well-known memory safety issue that has been historically exploited in kernel space to achieve privilege escalation.
Mitigation strategies for CVE-2024-49853 should focus on implementing proper reference counting mechanisms and resource tracking within the arm_scmi driver. The fix requires modifications to the channel descriptor cleanup logic to ensure that each descriptor is freed only once, regardless of whether it is shared between multiple protocols. System administrators should prioritize applying the kernel patches that address this issue, particularly on devices that rely heavily on secure firmware communication channels. The vulnerability demonstrates the importance of proper resource management in kernel modules and aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, as it provides a potential pathway for attackers to gain elevated privileges through memory corruption exploits. Organizations should also consider implementing runtime monitoring to detect anomalous memory patterns that might indicate exploitation attempts, as the double free condition could be used in conjunction with other techniques to achieve persistent access to system resources.