CVE-2026-80896 (GCVE-0-2026-80896)

Vulnerability from cvelistv5 – Published: 2026-09-04 17:11 – Updated: 2026-09-04 17:11
VLAI
Title
mshv: Fix race in mshv_irqfd_deassign
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 621191d709b14882270dfd8ea5d7d6cdfebe2c35 , < 72a90ce4918b5a2d4820fe20677ba9af780d8826 (git)
Affected: 621191d709b14882270dfd8ea5d7d6cdfebe2c35 , < 4529a41a675b96e0f876eef1cc93a31a57cb4d18 (git)
Affected: 621191d709b14882270dfd8ea5d7d6cdfebe2c35 , < 0762262ac3e70f65b3bb843fe892f8bac1562d08 (git)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "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."
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    "dateReserved": "2026-08-26T14:34:25.800Z",
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            "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": {},
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}



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