---
id: CVE-2026-64354
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Validate BTF repeated field counts before expansion

  btf_parse_struct_metas() walks user-supplied BTF during BPF_BTF_LOAD,
  and btf_repeat_fields() expands repeatab…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Validate BTF repeated field counts before expansion

  btf_parse_struct_metas() walks user-supplied BTF during BPF_BTF_LOAD,
  and btf_repeat_fields() expands repeatab…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
published: '2026-07-25'
updated: '2026-07-27'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64354'
references:
  - url: 'https://git.kernel.org/stable/c/b9452b594fd3aecbfd4aa0a6a1f741330a37dab7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c5ff816d5f13900c3f1f3298cfcc61339e056e56'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cd407de2ef5dc70f1970b343ffaa16186340fdfd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ff77d013b737c0f77d925e2f2c59f0cf3d76bd35'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00129
epssPercentile: 0.02083
ingestedAt: '2026-07-27T06:16:50.656Z'
---

## Overview

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

bpf: Validate BTF repeated field counts before expansion

btf_parse_struct_metas() walks user-supplied BTF during BPF_BTF_LOAD,
and btf_repeat_fields() expands repeatable fields from array elements
into the fixed BTF_FIELDS_MAX scratch array used by btf_parse_fields().

The remaining-capacity check performs the expanded field count calculation
in u32. A malformed BTF can wrap that calculation, causing the check to
pass even when the expanded field count exceeds the scratch array
capacity. The following memcpy() can then write past the end of the
array.

Use checked addition and multiplication before copying repeated fields
and reject impossible counts.

## Remediation

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