CVE-2026-98641

/// Technical description

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

bpf, arm64: set up the frame pointer for the exception callback

A program acting as exception boundary saves all callee-saved registers,

so build_prologue() takes the exception_cb path and never calls

push_callee_regs(). That is the only place find_used_callee_regs() runs,

and with it the only place ctx->fp_used is set, so the callback prologue

does not emit the

mov x25, sp

that points BPF_REG_FP at the frame the callback runs on. x25 keeps

whatever it held when bpf_throw() was called. If the throw came from a

subprogram that uses its own BPF stack, that is the subprogram's frame

pointer, and since the subprogram never returns it never restores x25

either.

Stack accesses through BPF_REG_FP are rewritten to be stack pointer

relative, so those still land in the callback's own frame. Materializing

the register does not: a callback that passes the address of a local

variable to a helper hands over an address in the

/// 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