CVE-2022-3636 in Linux
Summary
by MITRE • 10/21/2022
A vulnerability was identified in Linux Kernel 33fc42de33278b2b3ec6f3390512987bc29a62b7. This affects the function __mtk_ppe_check_skb of the file drivers/net/ethernet/mediatek/mtk_ppe.c of the component Ethernet Handler. Such manipulation leads to use after free. The name of the patch is 17a5f6a78dc7b8db385de346092d7d9f9dc24df6. It is best practice to apply a patch to resolve this issue. No released Linux Kernel version was ever affected by this CVE.
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Analysis
by VulDB Data Team • 07/28/2026
The vulnerability identified as CVE-2022-3636 represents a critical use after free condition within the Linux kernel's Ethernet handler component, specifically affecting the MediaTek Ethernet driver. This flaw exists in the __mtk_ppe_check_skb function located in drivers/net/ethernet/mediatek/mtk_ppe.c, which processes packets through the MediaTek Packet Processing Engine. The vulnerability stems from improper memory management where a pointer reference is maintained after the associated memory has been freed, creating a scenario where subsequent operations may access invalid memory locations. Such memory corruption vulnerabilities are particularly dangerous as they can lead to arbitrary code execution or system crashes, making them attractive targets for exploitation by malicious actors seeking to compromise system integrity.
The technical implementation of this vulnerability involves the MediaTek Packet Processing Engine's packet handling mechanism where the __mtk_ppe_check_skb function fails to properly validate memory references before performing operations on them. When network packets are processed through this component, the function may free memory associated with packet structures while maintaining references to those structures, creating a use after free condition. This pattern violates fundamental memory safety principles and aligns with CWE-416 which specifically addresses use after free vulnerabilities. The flaw occurs during the Ethernet packet processing lifecycle when the driver handles incoming network traffic through the MediaTek hardware components, making it particularly impactful for systems utilizing MediaTek Ethernet controllers.
From an operational perspective, this vulnerability presents a significant risk to system stability and security, especially in environments where the Linux kernel handles substantial network traffic. The use after free condition can be exploited to execute arbitrary code with kernel privileges, potentially leading to complete system compromise. Attackers could leverage this vulnerability to escalate privileges, gain persistent access, or cause denial of service conditions that would disrupt network operations. The impact extends beyond simple system crashes as the vulnerability allows for privilege escalation attacks that align with ATT&CK technique T1068 which covers exploit for privilege escalation. Systems utilizing MediaTek Ethernet hardware components are particularly at risk, including embedded devices, network appliances, and servers that rely on this specific driver implementation for network connectivity.
The recommended mitigation strategy involves applying the official kernel patch provided by the Linux kernel security team, which addresses the memory management issue in the __mtk_ppe_check_skb function. Organizations should prioritize updating their kernel versions to include the fix, particularly those running systems with MediaTek Ethernet controllers. Additionally, implementing network segmentation and monitoring can help detect potential exploitation attempts, though these measures serve as supplementary defenses rather than complete solutions. The patch implementation should be carefully tested in production environments to ensure compatibility with existing network configurations and hardware setups. Security teams should also consider deploying intrusion detection systems that monitor for anomalous network behavior patterns that might indicate exploitation attempts, as the vulnerability's exploitation could manifest through unusual packet processing patterns or memory access violations that align with ATT&CK technique T1005 which covers data from local system.