---
id: CVE-2026-98626
title: 'bpf: Restrict CO-RE poisoning to relocatable instructions'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Restrict CO-RE poisoning to relocatable instructions

  CO-RE relocation records can name any instruction offset. When a
  relocation cannot be resolved, bpf_core_patc…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f <
    a8c47e62d9aea2d47a09e06c1682c59c21b92449
  - >-
    Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f <
    d3219c229d16900cef936adad28633c98946e432
  - >-
    Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f <
    a0b79cdfcf34b53c85bac2d3cf022fc1342eeca0
  - >-
    Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f <
    f2a24101e89dd0804e717da7c1bd6af513698aa2
  - >-
    Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f <
    2d7d04357c41aa49a5ac658fcc207439f2ad6456
  - >-
    Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f <
    8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319
  - >-
    Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f <
    394ae398337c5f87e567f6cd63b937fc2b2f6ddc
  - Linux 5.6
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:19:47.832Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98626'
references:
  - url: 'https://git.kernel.org/stable/c/a8c47e62d9aea2d47a09e06c1682c59c21b92449'
  - url: 'https://git.kernel.org/stable/c/d3219c229d16900cef936adad28633c98946e432'
  - url: 'https://git.kernel.org/stable/c/a0b79cdfcf34b53c85bac2d3cf022fc1342eeca0'
  - url: 'https://git.kernel.org/stable/c/f2a24101e89dd0804e717da7c1bd6af513698aa2'
  - url: 'https://git.kernel.org/stable/c/2d7d04357c41aa49a5ac658fcc207439f2ad6456'
  - url: 'https://git.kernel.org/stable/c/8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319'
  - url: 'https://git.kernel.org/stable/c/394ae398337c5f87e567f6cd63b937fc2b2f6ddc'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.237Z'
---

## Overview

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

bpf: Restrict CO-RE poisoning to relocatable instructions

CO-RE relocation records can name any instruction offset. When a
relocation cannot be resolved, bpf_core_patch_insn() currently poisons its
target before checking whether that instruction is a valid relocation
target. Malformed metadata can therefore replace jumps, calls, exits,
register-source arithmetic, or non-immediate loads instead of failing at
the relocation step.

Handle poisoning only after the instruction has passed the same class and
operand-form checks used for a resolved relocation. Route invalid forms
through the existing diagnostic and return a hard error. Keep poisoning
supported instructions, including both halves of a plain ldimm64, so an
unresolved relocation in dead code remains valid.

Extend bpf_core_poison_insn() to poison both halves of ldimm64, and return
its status directly from each validated instruction case. This avoids
routing the success path through a common label and leaves the helper free
to report errors.

The shared relocation code applies this restriction to both libbpf and
in-kernel CO-RE.

## Affected

- `Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f < a8c47e62d9aea2d47a09e06c1682c59c21b92449`
- `Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f < d3219c229d16900cef936adad28633c98946e432`
- `Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f < a0b79cdfcf34b53c85bac2d3cf022fc1342eeca0`
- `Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f < f2a24101e89dd0804e717da7c1bd6af513698aa2`
- `Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f < 2d7d04357c41aa49a5ac658fcc207439f2ad6456`
- `Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f < 8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319`
- `Linux >= d7a252708dbc950ca2064310217e8b9f85846e2f < 394ae398337c5f87e567f6cd63b937fc2b2f6ddc`
- `Linux 5.6`

## Remediation

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