---
id: CVE-2026-98085
title: |-
  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} instruction…
summary: |-
  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} instruction…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ee861486e377edc55361c08dcbceab3f6b6577bd <
    671b7b9a660ef15b25faa3df161205b9dc8d1eb2
  - >-
    Linux >= ee861486e377edc55361c08dcbceab3f6b6577bd <
    387b1baefbb776e3f48dc2261e77a49213f470f7
  - Linux 928d354ae3557e8f755a227e67be88034eb3cd7f
  - Linux 8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe
  - Linux de1055e7f9e67af32b1f3376066272b04e5223c0
  - Linux 37ad2bb11e9de92cb7b94548705eeedd87f7d392
  - Linux 8674e2db06cff6b50f2216eed9a761d15425bb34
  - Linux ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337
  - Linux d846d83bdacbd8f14fc45c63b8c1d22608452e1c
  - Linux >= 5.10.265 < 5.11
  - Linux >= 5.15.216 < 5.16
  - Linux >= 6.1.183 < 6.2
  - Linux >= 6.6.148 < 6.7
  - Linux >= 6.12.101 < 6.13
  - Linux >= 6.18.42 < 6.19
  - Linux >= 7.0.10 < 7.1
  - Linux 7.1
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:38.087'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98085'
references:
  - url: 'https://git.kernel.org/stable/c/387b1baefbb776e3f48dc2261e77a49213f470f7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/671b7b9a660ef15b25faa3df161205b9dc8d1eb2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.834Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.