{"id":"CVE-2026-89754","revision":null,"records":[{"revision":"9ca42fa6a75a4cd7b4fcac37204a8e8c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89754","aliases":[],"title":"mm/pagewalk: fix stale walk->action escaping walk_pmd_range()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/pagewalk: fix stale walk->action escaping walk_pmd_range()\n\nIf ->pmd_entry() sets walk->action = ACTION_AGAIN, the pmd_none() check is\nretried.  The PMD entry may be cleared at the point of retry.\n\nIn this case, if walk->ops->install_pte is not specified, the code\ncontinues to the next PMD entry in the range without resetting\nwalk->action to ACTION_SUBTREE.\n\nThis leaves walk->action erroneously set to ACTION_AGAIN, which is\nincorrect.\n\nThis was incorrect but not problematic up until commit 3b89863c3fa4\n(\"mm/pagewalk: fix race between concurrent split and refault\") which\nupdated walk_pud_range() to check for walk->action == ACTION_AGAIN upon\nwalk_pmd_range()'s return, causing the PUD walk to be retried.\n\nIn this case this results in duplicate walk callbacks being invoked,\nwhich is erroneous and will break any caller that is not idempotent\nwith respect to this (and waste time for those which are).  The result\nis an out-of-bounds write, triggered by a local fuzzer:\n\n[    2.272695] ==================================================================\n[    2.273471] BUG: KASAN: slab-out-of-bounds in __mincore_unmapped_range+0x14f/0x190\n[    2.274302] Write of size 1 at addr ffff888008d9b000 by task poc/106\n[    2.274966]\n[    2.275154] CPU: 0 UID: 1000 PID: 106 Comm: poc Not tainted 7.2.0-rc6-00429-ga7c7074b58d2 #55 PREEMPT(lazy)\n[    2.275159] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[    2.275164] Call Trace:\n[    2.275170]  <TASK>\n[    2.275172]  dump_stack_lvl+0x53/0x70\n[    2.275200]  print_report+0xd0/0x630\n[    2.275210]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[    2.275219]  ? irqentry_exit+0xd2/0x670\n[    2.275224]  ? irqentry_exit+0xd2/0x670\n[    2.275226]  ? __virt_addr_valid+0xef/0x1a0\n[    2.275239]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275242]  kasan_report+0xce/0x100\n[    2.275245]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275248]  __mincore_unmapped_range+0x14f/0x190\n[    2.275252]  mincore_unmapped_range+0x45/0x70\n[    2.275254]  walk_pgd_range+0xafc/0xfc0\n[    2.275261]  ? __pfx_walk_pgd_range+0x10/0x10\n[    2.275264]  ? __update_load_avg_se+0x3d1/0x670\n[    2.275275]  __walk_page_range+0xc0/0x310\n[    2.275278]  ? __pfx_find_vma+0x10/0x10\n[    2.275281]  ? finish_task_switch.isra.0+0x16d/0x4f0\n[    2.275290]  walk_page_range_mm_unsafe+0x26f/0x3a0\n[    2.275293]  ? __pfx_mtree_load+0x10/0x10\n[    2.275298]  ? __pfx_walk_page_range_mm_unsafe+0x10/0x10\n[    2.275302]  ? __free_frozen_pages+0x54d/0x7e0\n[    2.275308]  __do_sys_mincore+0x132/0x380\n[    2.275311]  do_syscall_64+0xf9/0x540\n[    2.275316]  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[    2.275322] RIP: 0033:0x422ccd\n[    2.275326] Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48\n[    2.275329] RSP: 002b:00007fffffffec18 EFLAGS: 00000287 ORIG_RAX: 000000000000001b\n[    2.275337] RAX: ffffffffffffffda RBX: 0000000000000066 RCX: 0000000000422ccd\n[    2.275339] RDX: 00000000004d0940 RSI: 0000000001000000 RDI: 00007ffff4000000\n[    2.275340] RBP: 00000000004d0940 R08: 0000000000000100 R09: 0000000000000100\n[    2.275342] R10: 0000000000000100 R11: 0000000000000287 R12: 20c49ba5e353f7cf\n[    2.275343] R13: 00000000004990d3 R14: 0000000000000000 R15: 0000000000000001\n[    2.275346]  </TASK>\n[    2.275347]\n[    2.296904] The buggy address belongs to the object at ffff888008d9b000\n[    2.296904]  which belongs to the cache sigqueue of size 80\n[    2.298151] The buggy address is located 0 bytes inside of\n[    2.298151]  allocated 80-byte region [ffff888008d9b000, ffff888008d9b050)\n[    2.299408]\n[    2.299601] The buggy address belongs to the physical page:\n[    2.300191] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8d9b\n---truncated---","state":0,"publishedAt":"2026-09-11T19:46:57.534+00:00","modifiedAt":"2026-10-19T08:52:07.951+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/pagewalk.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"38ec58670a0c5fc1edabdeccd857e586b7b3f318\",\n                            \"lessThan\": \"895cd4ecbb2e03d7583103c65ee5adaae126ed6d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3b89863c3fa482912911cd65a12a3aeef662c250\",\n                            \"lessThan\": \"c05cdc2ab365b98099386e6c166b9865a4f2a9d3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3b89863c3fa482912911cd65a12a3aeef662c250\",\n                            \"lessThan\": \"aedf2efd18977e0cef7eb963166e2b1fcc0aa321\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9bbbebd94dd5be25ec8c899d46ef01b33d5d22c0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"6.18.21\",\n                            \"lessThan\": \"6.18.50\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.19.11\",\n                            \"lessThan\": \"6.20\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\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/pagewalk.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7.0\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"7.0\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\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/895cd4ecbb2e03d7583103c65ee5adaae126ed6d","https://git.kernel.org/stable/c/c05cdc2ab365b98099386e6c166b9865a4f2a9d3","https://git.kernel.org/stable/c/aedf2efd18977e0cef7eb963166e2b1fcc0aa321"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89754","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89754","identifiers":["CVE-2026-89754"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-0e1130a95bab4b43bc10624fd5ee853a","complete":false,"records":13654,"lastAttemptAt":"2026-11-09T04:16:03.8367163+00:00","lastSuccessAt":"2026-11-09T04:16:03.832+00:00","error":"8 identifier lookups failed; latest failures include HTTP 403. Other identifiers were checked independently.","lastVerifiedAt":"2026-11-09T04:16:03.832+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13653,"expectedIdentifiers":13706,"failedIdentifiers":8},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-09T04:03:51.7811525+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-09T04:03:51.7811525+00:00","lastSuccessAt":"2026-11-09T04:03:51.948408+00:00","error":null,"lastVerifiedAt":"2026-11-09T04:03:51.9484081+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-5a44a451442747cb81d83104fe1e7771","complete":true,"records":13666,"lastAttemptAt":"2026-11-09T04:03:52.3882913+00:00","lastSuccessAt":"2026-11-09T02:08:52.274+00:00","error":null,"lastVerifiedAt":"2026-11-09T02:08:52.274+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-09T04:03:51.3592849+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-09T04:03:51.3592849+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-09T04:02:14.6671491+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-09T04:02:14.6671491+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-3b1150af6d7ada2c07356cbab4ead5224c1485027890f71c71d0742cddf0b9e8","complete":true,"records":3055,"lastAttemptAt":"2026-11-09T04:03:51.7519249+00:00","lastSuccessAt":"2026-11-09T00:02:23.4330288+00:00","error":null,"lastVerifiedAt":"2026-11-09T04:03:51.7519249+00:00","snapshotPublishedAt":"2026-11-08T23:17:54+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-6a1c845b1938b1aa788f0e95c9ac8a8d5a1f07caed5d155840b0616b548c1455","complete":true,"records":231296,"lastAttemptAt":"2026-11-09T04:03:51.2380069+00:00","lastSuccessAt":"2026-11-09T04:03:49.859595+00:00","error":null,"lastVerifiedAt":"2026-11-09T04:03:51.2380069+00:00","snapshotPublishedAt":"2026-11-09T03:33:06+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}