---
id: CVE-2023-53186
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  skbuff: Fix a race between coalescing and releasing SKBs

  Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment
  recycling") allowed coalescing to proceed …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  skbuff: Fix a race between coalescing and releasing SKBs

  Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment
  recycling") allowed coalescing to proceed …
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-362
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.15, < 5.15.108'
  - 'linux_kernel >= 5.16, < 6.1.25'
  - 'linux_kernel >= 6.2, < 6.2.12'
  - linux_kernel = 6.3
patched:
  - linux_kernel 6.2.12
published: '2025-09-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:17:39.067'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-53186'
references:
  - url: 'https://git.kernel.org/stable/c/0646dc31ca886693274df5749cd0c8c1eaaeb5ca'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5f692c992a3bb9a8018e3488098b401a4229e7ec'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/71850b5af92da21b4862a9bc55bda61091247d00'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/906a6689bb0191ad2a44131a3377006aa098af59'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00267
epssPercentile: 0.18752
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:34:19.294430Z'
ingestedAt: '2026-10-15T22:48:25.400Z'
---

## Overview

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

skbuff: Fix a race between coalescing and releasing SKBs

Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment
recycling") allowed coalescing to proceed with non page pool page and page
pool page when @from is cloned, i.e.

to->pp_recycle    --> false
from->pp_recycle  --> true
skb_cloned(from)  --> true

However, it actually requires skb_cloned(@from) to hold true until
coalescing finishes in this situation. If the other cloned SKB is
released while the merging is in process, from_shinfo->nr_frags will be
set to 0 toward the end of the function, causing the increment of frag
page _refcount to be unexpectedly skipped resulting in inconsistent
reference counts. Later when SKB(@to) is released, it frees the page
directly even though the page pool page is still in use, leading to
use-after-free or double-free errors. So it should be prohibited.

The double-free error message below prompted us to investigate:
BUG: Bad page state in process swapper/1  pfn:0e0d1
page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000
index:0x2 pfn:0xe0d1
flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000
raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000
page dumped because: nonzero _refcount

CPU: 1 PID: 0 Comm: swapper/1 Tainted: G            E      6.2.0+
Call Trace:
 <IRQ>
dump_stack_lvl+0x32/0x50
bad_page+0x69/0xf0
free_pcp_prepare+0x260/0x2f0
free_unref_page+0x20/0x1c0
skb_release_data+0x10b/0x1a0
napi_consume_skb+0x56/0x150
net_rx_action+0xf0/0x350
? __napi_schedule+0x79/0x90
__do_softirq+0xc8/0x2b1
__irq_exit_rcu+0xb9/0xf0
common_interrupt+0x82/0xa0
</IRQ>
<TASK>
asm_common_interrupt+0x22/0x40
RIP: 0010:default_idle+0xb/0x20

## Affected

- `linux_kernel >= 5.15, < 5.15.108`
- `linux_kernel >= 5.16, < 6.1.25`
- `linux_kernel >= 6.2, < 6.2.12`
- `linux_kernel = 6.3`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.2.12`