---
id: CVE-2026-90201
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race

  This bug was discovered while testing the hns3 driver under channel
  reconfiguration (`etht…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race

  This bug was discovered while testing the hns3 driver under channel
  reconfiguration (`etht…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 4f51fb0d257ff4d406ec27966902de075e3b118e <
    bbfef303f980c1c078b8fa142e10a0e2fbcdd247
  - >-
    Linux >= ee62ce7a1d909ccba0399680a03c2dee83bcae95 <
    424a9fc4876cc7f28e9cb0aa8d92e920d726e350
  - >-
    Linux >= ee62ce7a1d909ccba0399680a03c2dee83bcae95 <
    9b65b0253ad5a66f73efee9a79a21a1e2b57cf59
  - >-
    Linux >= ee62ce7a1d909ccba0399680a03c2dee83bcae95 <
    24ef02f934eeb48830cff6b739abc3c62b1d107b
  - Linux c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4
  - Linux >= 6.12.34 < 6.12.110
  - Linux >= 6.15.3 < 6.16
  - Linux 6.16
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:17:15.053'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90201'
references:
  - url: 'https://git.kernel.org/stable/c/24ef02f934eeb48830cff6b739abc3c62b1d107b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/424a9fc4876cc7f28e9cb0aa8d92e920d726e350'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9b65b0253ad5a66f73efee9a79a21a1e2b57cf59'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bbfef303f980c1c078b8fa142e10a0e2fbcdd247'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.860Z'
epss: 0.002
epssPercentile: 0.10173
---

## Overview

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

net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race

This bug was discovered while testing the hns3 driver under channel
reconfiguration (`ethtool -L` / `ethtool -G`) with iperf3 traffic on
arm64. The race is intermittently triggered when page_pool_destroy()
runs page_pool_scrub() concurrently with page return via
page_pool_put_netmem() on a different CPU. A WARN in
page_pool_clear_pp_info() surfaced the dangling DMA index bits left
by the cmpxchg loser, which led to the investigation.

page_pool_scrub() iterates pool->dma_mapped via xa_for_each() with no
page ref held. __page_pool_release_netmem_dma() currently reads and
writes netmem fields (dma_addr, DMA index bits in pp_magic) after
xa_cmpxchg() returns. The unref path calls put_page() unconditionally
regardless of the cmpxchg outcome; when it loses the cmpxchg, it still
frees the page before the scrub winner finishes these netmem accesses,
so scrub touches a freed page -- a Use-After-Free.

Fix this by splitting the DMA release into two functions:

1. __page_pool_unmap_netmem_dma() caches dma_addr before xa_cmpxchg(),
   does the cmpxchg to remove the DMA mapping, and calls dma_unmap on
   the cached address. It never touches netmem fields after the cmpxchg,
   making it safe for the scrub path which holds no page ref.

2. __page_pool_release_netmem_dma() wraps the above and additionally
   clears dma_addr and DMA index bits in netmem fields. This is safe
   only when the caller holds a page ref, so it is used by the return
   path (page_pool_return_netmem).

The scrub path calls __page_pool_unmap_netmem_dma() directly; the return
path calls __page_pool_release_netmem_dma().

## Remediation

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