In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_u32: fix manual hash table handle IDR aliasing A u32 hash table… (CVE-2026-98629)

The Linux kernel vulnerability (CVE-2026-98629) affects the net/sched cls_u32 module, where a u32 hash table created with an explicit handle keys its IDR entry on the raw handle, but deletion frees it under a different key domain (handle2id(handle)). This mismatch causes manual tables to leak entries permanently and can cause deletion of unrelated auto-allocated tables. Consequently, later auto allocations may alias live manual tables, causing lookups and routing to the wrong table. The fix involves keying the divisor-path allocation on handle2id(handle) to unify the key domain, rejecting manual handles that map onto already used IDs, and ensuring auto allocation skips IDs held by live manual tables.

The vulnerability leads to permanent memory leaks in the kernel's traffic control subsystem and can cause incorrect routing of network traffic due to handle aliasing. This may affect network packet filtering and classification, potentially disrupting network operations or causing unexpected behavior in traffic control rules.

A fix is available that aligns the key domains used for manual and auto-allocated handles, preventing aliasing and leaks. Users should apply the official Linux kernel patch that addresses this issue. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation. Patch status is not explicitly stated in the input data; therefore, check the vendor advisory or Linux kernel mailing lists for the current patch availability and guidance.