CVE-2026-98589

/// Technical description

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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References