CVE-2026-90201

Full vulnerability record from the local CVENow database.

Description

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().

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-17 17:17:15.053000

Last modified

2026-10-19 09:19:10.163000

View original CVE JSON

{
  "id": "CVE-2026-90201",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-17T17:17:15.053",
  "lastModified": "2026-10-19T09:19:10.163",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race\n\nThis bug was discovered while testing the hns3 driver under channel\nreconfiguration (`ethtool -L` / `ethtool -G`) with iperf3 traffic on\narm64. The race is intermittently triggered when page_pool_destroy()\nruns page_pool_scrub() concurrently with page return via\npage_pool_put_netmem() on a different CPU. A WARN in\npage_pool_clear_pp_info() surfaced the dangling DMA index bits left\nby the cmpxchg loser, which led to the investigation.\n\npage_pool_scrub() iterates pool->dma_mapped via xa_for_each() with no\npage ref held. __page_pool_release_netmem_dma() currently reads and\nwrites netmem fields (dma_addr, DMA index bits in pp_magic) after\nxa_cmpxchg() returns. The unref path calls put_page() unconditionally\nregardless of the cmpxchg outcome; when it loses the cmpxchg, it still\nfrees the page before the scrub winner finishes these netmem accesses,\nso scrub touches a freed page -- a Use-After-Free.\n\nFix this by splitting the DMA release into two functions:\n\n1. __page_pool_unmap_netmem_dma() caches dma_addr before xa_cmpxchg(),\n   does the cmpxchg to remove the DMA mapping, and calls dma_unmap on\n   the cached address. It never touches netmem fields after the cmpxchg,\n   making it safe for the scrub path which holds no page ref.\n\n2. __page_pool_release_netmem_dma() wraps the above and additionally\n   clears dma_addr and DMA index bits in netmem fields. This is safe\n   only when the caller holds a page ref, so it is used by the return\n   path (page_pool_return_netmem).\n\nThe scrub path calls __page_pool_unmap_netmem_dma() directly; the return\npath calls __page_pool_release_netmem_dma()."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "net/core/page_pool.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "4f51fb0d257ff4d406ec27966902de075e3b118e",
              "lessThan": "bbfef303f980c1c078b8fa142e10a0e2fbcdd247",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "ee62ce7a1d909ccba0399680a03c2dee83bcae95",
              "lessThan": "424a9fc4876cc7f28e9cb0aa8d92e920d726e350",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "ee62ce7a1d909ccba0399680a03c2dee83bcae95",
              "lessThan": "9b65b0253ad5a66f73efee9a79a21a1e2b57cf59",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "ee62ce7a1d909ccba0399680a03c2dee83bcae95",
              "lessThan": "24ef02f934eeb48830cff6b739abc3c62b1d107b",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6.12.34",
              "lessThan": "6.12.110",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "6.15.3",
              "lessThan": "6.16",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "net/core/page_pool.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.16",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.16",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.110",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.52",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.6",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/24ef02f934eeb48830cff6b739abc3c62b1d107b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/424a9fc4876cc7f28e9cb0aa8d92e920d726e350",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9b65b0253ad5a66f73efee9a79a21a1e2b57cf59",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bbfef303f980c1c078b8fa142e10a0e2fbcdd247",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}