{"id":"CVE-2026-80896","state":"PUBLISHED","title":"mshv: Fix race in mshv_irqfd_deassign","description":"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->pt_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.","publishedAt":"2026-09-04T17:11:11.689Z","updatedAt":"2026-09-04T17:11:11.689Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"621191d709b14882270dfd8ea5d7d6cdfebe2c35","status":"affected","lessThan":"72a90ce4918b5a2d4820fe20677ba9af780d8826","versionType":"git"},{"version":"621191d709b14882270dfd8ea5d7d6cdfebe2c35","status":"affected","lessThan":"4529a41a675b96e0f876eef1cc93a31a57cb4d18","versionType":"git"},{"version":"621191d709b14882270dfd8ea5d7d6cdfebe2c35","status":"affected","lessThan":"0762262ac3e70f65b3bb843fe892f8bac1562d08","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_eventfd.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_eventfd.c"]}],"references":["https://git.kernel.org/stable/c/72a90ce4918b5a2d4820fe20677ba9af780d8826","https://git.kernel.org/stable/c/4529a41a675b96e0f876eef1cc93a31a57cb4d18","https://git.kernel.org/stable/c/0762262ac3e70f65b3bb843fe892f8bac1562d08"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80896.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80896","state":"PUBLISHED","datePublished":"2026-09-04T17:11:11.689Z","dateUpdated":"2026-09-04T17:11:11.689Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.800Z"},"containers":{"cna":{"title":"mshv: Fix race in mshv_irqfd_deassign","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->pt_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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"621191d709b14882270dfd8ea5d7d6cdfebe2c35","status":"affected","lessThan":"72a90ce4918b5a2d4820fe20677ba9af780d8826","versionType":"git"},{"version":"621191d709b14882270dfd8ea5d7d6cdfebe2c35","status":"affected","lessThan":"4529a41a675b96e0f876eef1cc93a31a57cb4d18","versionType":"git"},{"version":"621191d709b14882270dfd8ea5d7d6cdfebe2c35","status":"affected","lessThan":"0762262ac3e70f65b3bb843fe892f8bac1562d08","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_eventfd.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_eventfd.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/72a90ce4918b5a2d4820fe20677ba9af780d8826"},{"url":"https://git.kernel.org/stable/c/4529a41a675b96e0f876eef1cc93a31a57cb4d18"},{"url":"https://git.kernel.org/stable/c/0762262ac3e70f65b3bb843fe892f8bac1562d08"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-09-04T17:11:11.689Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}