{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74481","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-15T05:44:03.904Z","datePublished":"2026-08-15T12:27:14.441Z","dateUpdated":"2026-08-19T16:37:36.090Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-19T16:37:36.090Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_reporting: use system_freezable_wq to fix UAF during suspend\n\nDuring PM freeze (e.g.  S3 suspend or S4 hibernation), device drivers like\nvirtio_balloon reset their underlying virtio devices and delete their\nvirtqueues via vdev->config->del_vqs().\n\nHowever, page reporting work (page_reporting_process) was scheduled on the\nglobal system_wq.  Because system_wq lacks the WQ_FREEZABLE flag, the PM\nfreezer skips it, leaving page_reporting_process active during suspend.\n\nIf pages are freed into the buddy allocator while suspending (for example,\nwhen core MM invokes the balloon shrinker during S4 hibernation image\nsaving), page reporting triggers virtballoon_free_page_report() on deleted\nvirtqueues, resulting in a Use-After-Free / General Protection Fault:\n\n    [  196.795226] general protection fault, probably for non-canonical address 0xaa1436fe70dae6df: 0000 [#1] SMP NOPTI\n    [  196.825967] Workqueue: events page_reporting_process\n    [  196.831038] RIP: 0010:virtqueue_add_split+0x233/0x4c0 [virtio_ring]\n    [  196.927073] virtballoon_free_page_report+0x3a/0xe0 [virtio_balloon]\n    [  196.946943] page_reporting_process+0x370/0x4f0\n\nFix this by switching page reporting work to system_freezable_wq.  This\nensures that the PM freezer pauses page_reporting_process before device\ndrivers destroy their reporting virtqueues.  Because the reporting worker\nis frozen, memory reclamation/freeing (e.g.  via shrinker execution) can\nsafely return pages to MM during freeze without triggering unfrozen\nreporting work on deleted virtqueues.\n\nThis aligns with the driver's existing design. The comment in\nvirtballoon_freeze() states:\n    /*\n     * The workqueue is already frozen by the PM core before this\n     * function is called.\n     */\n\nTesting:\nI have verified these fixes using Google’s virtualization infrastructure\nby running continuous suspend/resume iterations (40+ cycles) while\nchurning memory using stress-ng (`stress-ng --vm 4 --vm-bytes 60%\n--timeout 1`) to constantly create free pages for the buddy allocator.  We\nalso set the `page_reporting_order` parameter to 0 to make the page\nreporting worker highly sensitive, forcing it to pick up any 4K free\npages.  This confirmed that the UAF crashes are no longer reproducible."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The UAF is reached only through local PM suspend/hibernation and guest memory-free paths (__free_one_page -> page_reporting_notify_free -> page_reporting_process -> virtballoon_free_page_report); it is not reachable via network protocols or remote packet handling.\nAC:L - An attacker with local access can reliably drive the race by churning memory (e.g. stress-ng) to flood page-reporting work while triggering or awaiting S3/S4 suspend, as demonstrated in the fix commit's reproduction on virtio-balloon VMs.\nPR:L - No real-root capability is required to exercise the memory-free entry path (normal unprivileged mmap/malloc/free syscalls), and many desktop deployments allow session users to initiate suspend via logind/polkit without full init-namespace root.\nUI:N - Exploitation does not require a separate victim action beyond the attacker (or system policy) initiating suspend/hibernation; automated cloud/VM suspend-resume cycles and scripted PM transitions suffice without interactive victim cooperation.\nS:U - Impact is confined to guest kernel memory corruption and crash inside the virtio-balloon/page-reporting subsystem; it does not cross a VM/host, IOMMU, or sandbox security boundary to affect resources outside the kernel's own authority.\nC:H - This is a kernel heap use-after-free on freed virtqueue metadata accessed through virtqueue_add_split; UAF of kernel objects can be leveraged for arbitrary kernel memory read/info disclosure beyond the observed GPF crash.\nI:H - UAF on virtqueue/vring kernel structures during virtqueue_add_split provides a memory-corruption primitive that can be developed into controlled kernel writes or code execution, not merely a benign crash.\nA:H - The bug provably causes a kernel general protection fault/oops in page_reporting_process during suspend (Workqueue: events), crashing or destabilizing the system and denying availability on every affected suspend/hibernation cycle."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_reporting.c"],"versions":[{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"a4c60046052777ca1dcc83fe3ece2a5136b301f1","status":"affected","versionType":"git"},{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"b2c094e98f8bb823b3ae475f7169fe2091c40c6d","status":"affected","versionType":"git"},{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"992f270fd808338fbae1f498a5e325e7e2e20368","status":"affected","versionType":"git"},{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"f978048326570047e8216e81a67f9c71ef2bb1b1","status":"affected","versionType":"git"},{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"450f35f4d5a682a0796757e52295df58ddb63bc9","status":"affected","versionType":"git"},{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"b11907c905fa08eda925395f0724b7a409870f65","status":"affected","versionType":"git"},{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"faf439b5fa7b231120eac4f7a617e0bfd4f6f5c7","status":"affected","versionType":"git"},{"version":"36e66c554b5c6a9d17a229faca7a61693527b0bd","lessThan":"0b45f6927a14914ff685fe0e6f9d11232a1e03df","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_reporting.c"],"versions":[{"version":"5.7","status":"affected"},{"version":"0","lessThan":"5.7","status":"unaffected","versionType":"semver"},{"version":"5.10.265","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.216","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.183","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.151","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.103","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.44","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.8","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.6.151"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a4c60046052777ca1dcc83fe3ece2a5136b301f1"},{"url":"https://git.kernel.org/stable/c/b2c094e98f8bb823b3ae475f7169fe2091c40c6d"},{"url":"https://git.kernel.org/stable/c/992f270fd808338fbae1f498a5e325e7e2e20368"},{"url":"https://git.kernel.org/stable/c/f978048326570047e8216e81a67f9c71ef2bb1b1"},{"url":"https://git.kernel.org/stable/c/450f35f4d5a682a0796757e52295df58ddb63bc9"},{"url":"https://git.kernel.org/stable/c/b11907c905fa08eda925395f0724b7a409870f65"},{"url":"https://git.kernel.org/stable/c/faf439b5fa7b231120eac4f7a617e0bfd4f6f5c7"},{"url":"https://git.kernel.org/stable/c/0b45f6927a14914ff685fe0e6f9d11232a1e03df"}],"title":"mm/page_reporting: use system_freezable_wq to fix UAF during suspend","x_generator":{"engine":"bippy-1.2.0"}}}}