CVE-2026-98599
Received
Received - Intake
BPF Stack Slot Object Validation Bypass
Vulnerability report for CVE-2026-98599, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-18
Last updated on: 2026-10-18
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject non-negative offsets in stack_slot_obj_get_spi()
bpf_get_spi() computes (-off - 1) / BPF_REG_SIZE using C division,
which truncates toward zero. For off == 0, this produces spi 0, the
same index used by the valid stack slot at fp-8.
stack_slot_obj_get_spi() currently checks alignment and the resulting
spi bounds, but does not reject the non-negative offset itself. It can
therefore validate a PTR_TO_STACK register holding fp+0 against an
iterator stored at fp-8 even though the runtime receives the actual fp+0
pointer. An effectful iterator kfunc can then interpret memory outside
the BPF stack as iterator state.
Reject non-negative offsets before converting the offset to an spi. All
valid stack objects begin at a negative offset from the frame pointer.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Linux | Linux | 06accc8779c1d558a5b5a21f2ac82b0c95827ddd |
| Linux | Linux | 06accc8779c1d558a5b5a21f2ac82b0c95827ddd |
| Linux | Linux | 6.4 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
