Robustness Fix in Linux Kernel for NAT Helpers Issue

CVE-2026-53349

What is CVE-2026-53349?

A robustness issue in the Linux kernel's NAT helpers involves stale expectations remaining in the expectation table upon module removal. Specifically, when NAT helpers, such as nf_nat_h323, are unloaded while active connections exist, they leave behind dangling pointers to freed module text. This can lead to severe errors when the connection attempts to invoke a function that no longer exists. The introduction of nf_ct_helper_expectfn_destroy() addresses this by ensuring that all expectations referencing the unloaded module are properly cleared, thus preventing any potential crashes or unexpected behavior during network operations.

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