CVE-2024-49997 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: lantiq_etop: fix memory disclosure
When applying padding, the buffer is not zeroed, which results in memory disclosure. The mentioned data is observed on the wire. This patch uses skb_put_padto() to pad Ethernet frames properly. The mentioned function zeroes the expanded buffer.
In case the packet cannot be padded it is silently dropped. Statistics are also not incremented. This driver does not support statistics in the old 32-bit format or the new 64-bit format. These will be added in the future. In its current form, the patch should be easily backported to stable versions.
Ethernet MACs on Amazon-SE and Danube cannot do padding of the packets in hardware, so software padding must be applied.
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Analysis
by VulDB Data Team • 03/22/2026
The vulnerability identified as CVE-2024-49997 affects the Linux kernel's lantiq_etop driver which manages Ethernet MACs on specific hardware platforms including Amazon-SE and Danube SoCs. This issue represents a memory disclosure vulnerability that occurs when the driver processes Ethernet frames requiring padding. The flaw stems from improper buffer management during packet padding operations where the allocated buffer space is not properly initialized with zeros before padding is applied. This creates a situation where residual data from previous memory operations may be exposed on the network wire, potentially revealing sensitive information from kernel memory regions or other processes running on the system.
The technical implementation of this vulnerability involves the lantiq_etop driver's handling of Ethernet frame padding operations on hardware platforms that lack hardware support for automatic packet padding. When packets require padding to meet minimum frame size requirements, the driver attempts to apply software padding but fails to zero the newly allocated buffer space. This memory disclosure occurs because the driver uses a method that does not properly initialize the padding bytes, allowing uninitialized memory contents to be transmitted as part of the Ethernet frame. The patch addresses this by implementing skb_put_padto() function which correctly handles the padding operation while ensuring that any expanded buffer space is properly zeroed, thereby eliminating the exposure of sensitive data.
The operational impact of this vulnerability extends beyond simple information disclosure as it represents a potential security risk for systems utilizing the affected hardware platforms. Network traffic passing through these systems could inadvertently expose kernel memory contents to external observers, potentially revealing system information, cryptographic keys, or other sensitive data. The vulnerability affects systems running Linux kernels with the lantiq_etop driver, particularly those deployed on Amazon-SE and Danube SoC platforms where hardware padding capabilities are absent. The patch implementation ensures that when padding operations cannot be completed successfully, packets are silently dropped without incrementing statistics, maintaining the integrity of the network stack while preventing the exposure of memory contents.
Security implications of this vulnerability align with CWE-200 (Information Exposure) and can be mapped to ATT&CK technique T1041 (Exfiltration Over C2 Channel) through potential data leakage mechanisms. The patch addresses the core issue by utilizing the skb_put_padto() function which provides proper buffer management and zero-initialization during padding operations. This solution represents a defensive programming approach that prevents uninitialized memory from being transmitted over the network. The mitigation strategy is designed to be easily backportable to stable kernel versions, ensuring that organizations running older kernel versions can apply the fix without significant compatibility concerns. The driver's current limitation regarding statistics support does not impact the core security fix, though future implementations may need to address the missing 32-bit and 64-bit statistics support as mentioned in the patch description.