CVE-2026-80670

In the Linux kernel, the following vulnerability has been resolved:

perf tools: Use perf_env__get_cpu_topology() in machine__resolve()

machine__resolve() accesses env->cpu[al->cpu].socket_id after checking
al->cpu >= 0 and env->cpu != NULL, but without validating al->cpu
against env->nr_cpus_avail.  Since al->cpu comes from the untrusted
perf.data sample, a crafted file with a large CPU index causes an
out-of-bounds heap read.

Use perf_env__get_cpu_topology() which validates both NULL and bounds.
Also bounds-check al->cpu before the cast to struct perf_cpu (int16_t):
without this, values like 65536 silently truncate to 0, bypassing the
accessor's internal check and returning CPU 0's topology.