CVE-2026-98085
Received
Received - Intake
BPF Precision Backtracking Flaw in Linux Kernel
Vulnerability report for CVE-2026-98085, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-25
Last updated on: 2026-09-25
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge
Nicholas Carlini reported a bug in precision backtracking mechanism
for BPF_LD | BPF_{IND,ABS} instructions. These instructions are
modelled as two branches:
- fallthrough;
- implicit exit from current subprogram.
The implicit exit case was not handled by the backtrack_insn()
function. When backtracking such a path backtrack_insn() did not
call bt_subprog_enter(), which meant that backtracking continued
manipulating precision marks in a caller frame, while looking at
instructions in a callee frame.
This lead to segmentation faults during verification (see the
selftest), or unsound state pruning.
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
