{"id":"CVE-2026-74481","revision":"f8d40d1e264b40bc9ff7aafd038dffcd","records":[{"revision":"f8d40d1e264b40bc9ff7aafd038dffcd","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-74481","aliases":[],"title":"mm/page_reporting: use system_freezable_wq to fix UAF during suspend","description":"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.","state":0,"publishedAt":"2026-08-15T12:27:14.441+00:00","modifiedAt":"2026-10-16T19:05:48.983+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"mm/page_reporting.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"a4c60046052777ca1dcc83fe3ece2a5136b301f1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"b2c094e98f8bb823b3ae475f7169fe2091c40c6d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"992f270fd808338fbae1f498a5e325e7e2e20368\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"f978048326570047e8216e81a67f9c71ef2bb1b1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"450f35f4d5a682a0796757e52295df58ddb63bc9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"b11907c905fa08eda925395f0724b7a409870f65\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"faf439b5fa7b231120eac4f7a617e0bfd4f6f5c7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"36e66c554b5c6a9d17a229faca7a61693527b0bd\",\n                            \"lessThan\": \"0b45f6927a14914ff685fe0e6f9d11232a1e03df\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"mm/page_reporting.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.7\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.7\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.265\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.216\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.183\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.151\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.103\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.44\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.8\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/a4c60046052777ca1dcc83fe3ece2a5136b301f1","https://git.kernel.org/stable/c/b2c094e98f8bb823b3ae475f7169fe2091c40c6d","https://git.kernel.org/stable/c/992f270fd808338fbae1f498a5e325e7e2e20368","https://git.kernel.org/stable/c/f978048326570047e8216e81a67f9c71ef2bb1b1","https://git.kernel.org/stable/c/450f35f4d5a682a0796757e52295df58ddb63bc9","https://git.kernel.org/stable/c/b11907c905fa08eda925395f0724b7a409870f65","https://git.kernel.org/stable/c/faf439b5fa7b231120eac4f7a617e0bfd4f6f5c7","https://git.kernel.org/stable/c/0b45f6927a14914ff685fe0e6f9d11232a1e03df"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74481","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-74481","identifiers":["CVE-2026-74481"]},"retained":false,"historicalAffected":[]}],"coverage":[]}