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FKIE_CVE-2026-80896

Vulnerability from fkie_nvd - Published: 2026-09-04 18:17 - Updated: 2026-09-04 18:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: mshv: Fix race in mshv_irqfd_deassign mshv_irqfd_deactivate() and the hlist traversal of pt_irqfds_list require pt->pt_irqfds_lock to be held, but mshv_irqfd_deassign() omits it. This races with the EPOLLHUP path in mshv_irqfd_wakeup(), which does take the lock before calling mshv_irqfd_deactivate(). Additionally, mshv_irqfd_deactivate() uses hlist_del() which poisons the node pointers rather than resetting them. Since mshv_irqfd_is_active() relies on hlist_unhashed() (checks pprev == NULL), a poisoned node still appears active. If a concurrent path calls mshv_irqfd_deactivate() again on the same irqfd, the guard fails to prevent a double hlist_del() on poisoned pointers. Fix both issues: - Add the missing spin_lock_irq/spin_unlock_irq around the list traversal in mshv_irqfd_deassign(), matching mshv_irqfd_release(). - Use hlist_del_init() instead of hlist_del() so the node is properly marked as unhashed after removal, making the is_active guard reliable.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0762262ac3e70f65b3bb843fe892f8bac1562d08
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4529a41a675b96e0f876eef1cc93a31a57cb4d18
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/72a90ce4918b5a2d4820fe20677ba9af780d8826
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/hv/mshv_eventfd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "72a90ce4918b5a2d4820fe20677ba9af780d8826",
              "status": "affected",
              "version": "621191d709b14882270dfd8ea5d7d6cdfebe2c35",
              "versionType": "git"
            },
            {
              "lessThan": "4529a41a675b96e0f876eef1cc93a31a57cb4d18",
              "status": "affected",
              "version": "621191d709b14882270dfd8ea5d7d6cdfebe2c35",
              "versionType": "git"
            },
            {
              "lessThan": "0762262ac3e70f65b3bb843fe892f8bac1562d08",
              "status": "affected",
              "version": "621191d709b14882270dfd8ea5d7d6cdfebe2c35",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/hv/mshv_eventfd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmshv: Fix race in mshv_irqfd_deassign\n\nmshv_irqfd_deactivate() and the hlist traversal of pt_irqfds_list\nrequire pt-\u003ept_irqfds_lock to be held, but mshv_irqfd_deassign()\nomits it. This races with the EPOLLHUP path in mshv_irqfd_wakeup(),\nwhich does take the lock before calling mshv_irqfd_deactivate().\n\nAdditionally, mshv_irqfd_deactivate() uses hlist_del() which poisons\nthe node pointers rather than resetting them. Since\nmshv_irqfd_is_active() relies on hlist_unhashed() (checks pprev ==\nNULL), a poisoned node still appears active. If a concurrent path calls\nmshv_irqfd_deactivate() again on the same irqfd, the guard fails to\nprevent a double hlist_del() on poisoned pointers.\n\nFix both issues:\n- Add the missing spin_lock_irq/spin_unlock_irq around the list\n  traversal in mshv_irqfd_deassign(), matching mshv_irqfd_release().\n- Use hlist_del_init() instead of hlist_del() so the node is properly\n  marked as unhashed after removal, making the is_active guard reliable."
    }
  ],
  "id": "CVE-2026-80896",
  "lastModified": "2026-09-04T18:17:57.847",
  "metrics": {},
  "published": "2026-09-04T18:17:57.847",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0762262ac3e70f65b3bb843fe892f8bac1562d08"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4529a41a675b96e0f876eef1cc93a31a57cb4d18"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/72a90ce4918b5a2d4820fe20677ba9af780d8826"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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