CVE-2026-98007

About vulnerability

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

bpf: Reject non-scalar bpf_loop iteration counts

bpf_loop() declares its nr_loops argument as ARG_ANYTHING. Privileged programs may pass pointer values to such arguments, so check_func_arg() lets a pointer-valued R1 reach the helper-specific checks.

Since commit bb124da69c47 (“bpf: keep track of max number of bpf_loop callback iterations”), the verifier marks R1 precise and reads its upper bound to limit callback simulation. Precision backtracking only accepts scalar registers, so passing a pointer instead triggers the “backtracking misuse” verifier warning. Kernels with panic_on_warn enabled subsequently panic.

Introduce ARG_SCALAR for helper arguments that only accept scalar values and use it for bpf_loop() nr_loops. Generic helper argument validation then rejects pointers before loop inlining and precision processing.

Affected product:

AlmaLinux 9.2 ESU , TuxCare 9.6 ESU , TuxCare 9.8 ESU

Affected packages:

kernel @ 5.14.0 (+2 more)

Live-patch status from KernelCare for each operating system.