---
id: CVE-2026-98042
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Don't resurrect a scalar id dropped by collect_linked_regs()

  check_cond_jmp_op() copies the compared registers into
  env->{false,true}_reg{1,2} before collect_link…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Don't resurrect a scalar id dropped by collect_linked_regs()

  check_cond_jmp_op() copies the compared registers into
  env->{false,true}_reg{1,2} before collect_link…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ec1d77cb0ee98249142dcd0376d76e7a48ba0b31 <
    e821ff19b8ef08255ff8d8234774ed814637e9bf
  - >-
    Linux >= ec1d77cb0ee98249142dcd0376d76e7a48ba0b31 <
    73a98f96811e2cb0f4210b1caa8cb322f92f2a2b
  - Linux 7.1
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:32.987'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98042'
references:
  - url: 'https://git.kernel.org/stable/c/73a98f96811e2cb0f4210b1caa8cb322f92f2a2b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e821ff19b8ef08255ff8d8234774ed814637e9bf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.849Z'
---

## Overview

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

bpf: Don't resurrect a scalar id dropped by collect_linked_regs()

check_cond_jmp_op() copies the compared registers into
env->{false,true}_reg{1,2} before collect_linked_regs() runs and copies
those snapshots back into both branch states afterwards.

collect_linked_regs() records at most LINKED_REGS_MAX members of a
linked registers group in the jump history and calls clear_scalar_id()
for every member that does not fit. The compared register is not exempt
from that.

As a consequence, sync_linked_regs() might adjust ranges for more
registers than bpf_bt_sync_linked_regs() can propagate precision to.

Collect the linked registers before the snapshots are taken instead.
This might lead to some unnecessary clear_scalar_id's, but from
previous testing situations with many linked registers are
extremely rare.

## Remediation

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