CVE-2026-98589

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

bpf: Reject pkt arguments in mutating subprogs

The verifier tracks changes in how PTR_TO_PACKET registers'

bounds are modified across subprog boundaries. PTR_TO_PACKET

registers are actually passed as PTR_TO_MEM, which is assumed

valid for the entire call. This is not the case with packet memory,

where a pskb_* call may invalidate its memory region.

Reject BPF code that passes PTR_TO_PACKET pointers to subprogs that

may mutate a packet. We cannot pass the pointer as a true PTR_TO_PACKET

because we would also need to somehow pass the PTR_TO_PACKET_META

or PTR_TO_PACKET_END to the subprog. Since we cannot avoid representing

the pointer in the subprog as PTR_TO_MEM, only permit it if the

subprog is guaranteed not to mutate the packet.