Linux Kernel EROFS Vulnerability in Nydus Product

CVE-2026-80899

What is CVE-2026-80899?

A vulnerability in the Linux kernel involves the deprecation of the fscache backend for the EROFS file system. Initially introduced to facilitate image lazy pulling, the feature created an unexpected dependency on the netfs subsystem, complicating local file system operations. Due to the existence of alternatives, namely fanotify pre-content hooks which provide equivalent functionality, the fscache backend has been removed. This decision not only simplifies the codebase but also aligns with Nydus's transition towards utilizing fanotify for enhanced reliability. This change aims to streamline EROFS functionality while addressing previously noted implementation issues.

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