{ "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" } } } }