CVE-2026-98075

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

bpf: reject BPF PSEUDO FUNC reference to the main program

fixups.c:jit subprogs() rewrites BPF PSEUDO FUNC loads to contain real function addresses. This function is invoked from bpf jit subprogs() only when env->subprog cnt > 1. Meaning that for any program like below:

int main(void *ctx) { void *ptr = main; ... bpf timer set callback(..., ptr); ... }

The 'ptr' won't be ever converted to contain an address. In combination with e.g. bpf timer set callback() this would lead to a function call at a bogus address.

Instead of complicating the implementation, just assume that no useful program needs main to be a sync or async callback and reject BPF PSEUDO FUNC loads for the main subprogram.