Linux Kernel Vulnerability in Net Component Affecting Data Integrity

CVE-2026-63830

What is CVE-2026-63830?

A vulnerability has been identified in the Linux kernel's handling of the scatterlist (sg) entries in the net component, which may allow for improper exposure of data. The sk_msg sg.copy bitmap is crucial for maintaining the ownership state of scatterlist entries. Certain transformation paths used in sk_msg may not update the corresponding sg.copy bits correctly when entries are manipulated, which can lead to an externally backed entry being exposed as writable in the BPF context. This exposure could permit unauthorized modifications to the original page cache, potentially leading to severe data integrity issues. The issue highlights the importance of synchronizing the sg.copy bitmap with the associated sg.data[] entries during any transformations to prevent unintended data leaks.

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