UBUNTU-CVE-2026-98149: High severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix percpu map update indexing with sparse CPU IDs Per-CPU array, hash, and cgroup storage map updates without BPFFCPU or BPFFALLCPUS use a value buffer whose per-CPU slots are packed in possible-CPU order. The buffer is sized as: roundup(valuesize, 8) numpossiblecpus() The update paths iterate over possible CPUs, but use the logical CPU ID to calculate the source offset: value + size cpu This only works when possible CPU IDs are contiguous starting at zero. For example, with a possible CPU mask of 0,2-3, the buffer contains three slots corresponding to CPUs 0, 2, and 3. CPU2 is therefore expected to use slot 1 and CPU3 slot 2. Instead, the current code uses slots 2 and 3 respectively, causing incorrect per-CPU values and an out-of-bounds read from the update buffer for CPU3. The corresponding lookup paths already use a dense offset while iterating over possible CPUs. Do the same for the array, hash, and cgroup storage update paths, advancing the source offset once for each possible CPU. BPFFALLCPUS continues to use the same value for every CPU.