CVE intelligence

CVE-2026-98599

Vulnerability intelligence

Published Oct 18, 2026Sources checked Oct 21, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-98599. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 20, 2026

Release Notes

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-98599?

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.

Source: NVD