---
id: CVE-2026-98063
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Fix NULL-ptr-deref in btf_var_show()

  btf_var_show() calls btf_type_id_resolve() unconditionally, which
  dereferences btf->resolved_ids
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Fix NULL-ptr-deref in btf_var_show()

  btf_var_show() calls btf_type_id_resolve() unconditionally, which
  dereferences btf->resolved_ids. That is NULL for a base BTF…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= c4d0bfb45068d853a478b9067a95969b1886a30f <
    e472ae0d97865e2021ee668a13eab64013aebf23
  - >-
    Linux >= c4d0bfb45068d853a478b9067a95969b1886a30f <
    ca086264e98108b44fdf53971033811a48defe2b
  - >-
    Linux >= c4d0bfb45068d853a478b9067a95969b1886a30f <
    ea383b3ea56979ce54c8aa88e6ec67164986c401
  - >-
    Linux >= c4d0bfb45068d853a478b9067a95969b1886a30f <
    5403a383f52fc0905703b488f7c3db4b2447dc58
  - Linux 5.10
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:35.327'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98063'
references:
  - url: 'https://git.kernel.org/stable/c/5403a383f52fc0905703b488f7c3db4b2447dc58'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ca086264e98108b44fdf53971033811a48defe2b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e472ae0d97865e2021ee668a13eab64013aebf23'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ea383b3ea56979ce54c8aa88e6ec67164986c401'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.843Z'
---

## Overview

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

bpf: Fix NULL-ptr-deref in btf_var_show()

btf_var_show() calls btf_type_id_resolve() unconditionally, which
dereferences btf->resolved_ids. That is NULL for a base BTF - e.g. the
vmlinux BTF that bpf_snprintf_btf() renders against - since base BTF is
not resolved during parsing. btf_modifier_show() guards this with
'if (btf->resolved_ids)', but btf_var_show() does not.

A BPF program that passes the type_id of a BTF_KIND_VAR from the vmlinux
BTF to bpf_snprintf_btf() thus NULL-derefs:

KASAN: probably user-memory-access in range [0x46638-0x4663f]
RIP: 0010:btf_var_show (kernel/bpf/btf.c:2929)
Call Trace:
 <TASK>
 btf_type_show (kernel/bpf/btf.c:8259)
 btf_type_snprintf_show (kernel/bpf/btf.c:8329)
 bpf_snprintf_btf (kernel/trace/bpf_trace.c:1047)
 bpf_prog_test_run_raw_tp (net/bpf/test_run.c:829)
 __sys_bpf (kernel/bpf/syscall.c:4804)
 do_syscall_64 (arch/x86/entry/syscall_64.c:84)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
 </TASK>

Resolve the var's type directly with btf_type_skip_modifiers() when
resolved_ids is NULL, mirroring btf_modifier_show().

## Remediation

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