---
id: CVE-2026-23383
title: 'bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing

  struct bpf_plt contains a u64 target field. Currently, the BPF JIT
  allocator requests an al…
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 <
    f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d
  - >-
    Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 <
    80ad264da02cc4aee718e799c2b79f0f834673dc
  - >-
    Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 <
    519b1ad91de5bf7a496f2b858e9212db6328e1de
  - >-
    Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 <
    66959ed481a474eaae278c7f6860a2a9b188a4d6
  - >-
    Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 <
    ef06fd16d48704eac868441d98d4ef083d8f3d07
  - Linux 6.0
published: '2026-03-25'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:39:11.598Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23383'
references:
  - url: 'https://git.kernel.org/stable/c/f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d'
  - url: 'https://git.kernel.org/stable/c/80ad264da02cc4aee718e799c2b79f0f834673dc'
  - url: 'https://git.kernel.org/stable/c/519b1ad91de5bf7a496f2b858e9212db6328e1de'
  - url: 'https://git.kernel.org/stable/c/66959ed481a474eaae278c7f6860a2a9b188a4d6'
  - url: 'https://git.kernel.org/stable/c/ef06fd16d48704eac868441d98d4ef083d8f3d07'
tags:
  - cve.org
epss: 0.00129
epssPercentile: 0.02228
ingestedAt: '2026-10-21T12:48:53.667Z'
---

## Overview

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

bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing

struct bpf_plt contains a u64 target field. Currently, the BPF JIT
allocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT
buffer.

Because the base address of the JIT buffer can be 4-byte aligned (e.g.,
ending in 0x4 or 0xc), the relative padding logic in build_plt() fails
to ensure that target lands on an 8-byte boundary.

This leads to two issues:
1. UBSAN reports misaligned-access warnings when dereferencing the
   structure.
2. More critically, target is updated concurrently via WRITE_ONCE() in
   bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64,
   64-bit loads/stores are only guaranteed to be single-copy atomic if
   they are 64-bit aligned. A misaligned target risks a torn read,
   causing the JIT to jump to a corrupted address.

Fix this by increasing the allocation alignment requirement to 8 bytes
(sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of
the JIT buffer to an 8-byte boundary, allowing the relative padding math
in build_plt() to correctly align the target field.

## Affected

- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d`
- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 80ad264da02cc4aee718e799c2b79f0f834673dc`
- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 519b1ad91de5bf7a496f2b858e9212db6328e1de`
- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 66959ed481a474eaae278c7f6860a2a9b188a4d6`
- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < ef06fd16d48704eac868441d98d4ef083d8f3d07`
- `Linux 6.0`

## Remediation

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