Linux Kernel Vulnerability in Vsock Handling

CVE-2026-53365

What is CVE-2026-53365?

CVE-2026-53365 is a vulnerability identified in the Linux kernel's handling of Virtual Socket (vsock) operations. The primary purpose of vsock is to facilitate communication between virtual machines and the host operating system. This vulnerability arises from inadequate management of memory associated with large messages segmented into multiple socket buffers (skbs). When such messages are sent, only the last segment correctly handles memory allocation for zero-copy operations, leaving earlier segments without proper completion tracking. As a result, this oversight can lead to leaked pinned user pages, creating a scenario where the kernel fails to notify the user-space environment when these pages are no longer in use. This can severely disrupt memory management in an affected system, exposing organizations to potential exploitation risks.

Potential impact of CVE-2026-53365

1. Memory Leakage: The vulnerability may result in pinned user pages not being released appropriately, leading to memory leaks. This can degrade system performance and stability, especially in environments where memory resources are critical.

2. Denial of Service: By overwhelming the kernel's resources through the manipulation of this vulnerability, an attacker could induce a denial-of-service condition on the host system, preventing legitimate operations and affecting overall system availability.

3. Increased Attack Surface: With the potential for exploitation due to the mishandling of memory, adversaries might gain unauthorized access or privilege escalation opportunities, increasing the likelihood of further attacks on sensitive system components or data.

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