---
id: CVE-2026-98037
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Reject untrusted allocated-object pointers

  When the final RCU read-side critical section ends, a local kptr is demoted
  to PTR_UNTRUSTED but retains MEM_ALLOC
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Reject untrusted allocated-object pointers

  When the final RCU read-side critical section ends, a local kptr is demoted
  to PTR_UNTRUSTED but retains MEM_ALLOC. The…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1b12171533a9bb23cf6fba7262b479028b65e1e8 <
    092c2874dc1b2060fa77a465a971acd4fdf87683
  - >-
    Linux >= 1b12171533a9bb23cf6fba7262b479028b65e1e8 <
    135d542b97fa93e32c457d49d6e7b33ca7d05bae
  - >-
    Linux >= 1b12171533a9bb23cf6fba7262b479028b65e1e8 <
    6b1f786ad85a0b63393b76f5e634deab1a73198c
  - >-
    Linux >= 1b12171533a9bb23cf6fba7262b479028b65e1e8 <
    7441ee8276641bddaf1cba7bb75ef9c1458ceb3b
  - Linux 6.8
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:32.443'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98037'
references:
  - url: 'https://git.kernel.org/stable/c/092c2874dc1b2060fa77a465a971acd4fdf87683'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/135d542b97fa93e32c457d49d6e7b33ca7d05bae'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6b1f786ad85a0b63393b76f5e634deab1a73198c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7441ee8276641bddaf1cba7bb75ef9c1458ceb3b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.850Z'
---

## Overview

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

bpf: Reject untrusted allocated-object pointers

When the final RCU read-side critical section ends, a local kptr is demoted
to PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer
to an object whose lifetime is no longer protected.

type_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with
MEM_ALLOC as a live allocated object. In particular, a refcount-only local
kptr never carries NON_OWN_REF, so it still passes the
bpf_refcount_acquire() argument check after RCU protection ends. The kfunc
can then dereference NULL or stale memory.

Make type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since
type_is_non_owning_ref() is based on the same predicate, graph kfunc
arguments obey the same live-object requirement. Fault-protected reads of
the demoted pointer remain valid: writes are already rejected, and read
fixups use bpf_may_fault_on_deref() rather than this predicate.

[ kkd: Rewrote commit log ]

## Remediation

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