{"api_version":"1","generated_at":"2026-07-28T10:53:10+00:00","cve":"CVE-2026-64418","urls":{"html":"https://cve.report/CVE-2026-64418","api":"https://cve.report/api/cve/CVE-2026-64418.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64418","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64418"},"summary":{"title":"mm: shrinker: fix shrinker_info teardown race with expansion","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: shrinker: fix shrinker_info teardown race with expansion\n\nexpand_shrinker_info() iterates all visible memcgs under shrinker_mutex,\nincluding memcgs that have not finished ->css_online() yet.\n\nOnce pn->shrinker_info has been published, teardown must stay serialized\nwith expand_shrinker_info() until that memcg is either fully online or no\nlonger visible to iteration.  Today alloc_shrinker_info() breaks that rule\nby dropping shrinker_mutex before freeing a partially initialized\nshrinker_info array, which may cause the following race:\n\nCPU0                   CPU1\n====                   ====\n\ncss_create\n--> list_add_tail_rcu(&css->sibling, &parent_css->children);\n    online_css\n    --> mem_cgroup_css_online\n        --> alloc_shrinker_info\n            --> alloc node0 info\n                rcu_assign_pointer(C->node0->shrinker_info, old0)\n                alloc node1 info -> FAIL -> goto err\n                mutex_unlock(shrinker_mutex)\n\n                       shrinker_alloc()\n                       --> shrinker_memcg_alloc\n                           --> mutex_lock(shrinker_mutex)\n                               expand_shrinker_info\n                               --> mem_cgroup_iter see the memcg\n                                   expand_one_shrinker_info\n                                   --> old0 = C->node0->shrinker_info\n                                       memcpy(new->unit, old0->unit, ...);\n\n                free_shrinker_info\n                --> kvfree(old0);\n\n                                       /* double free !! */\n                                       kvfree_rcu(old0, rcu);\n\nThe same problem exists later in mem_cgroup_css_online().  If\nalloc_shrinker_info() succeeds but a subsequent objcg allocation fails,\nthe free_objcg -> free_shrinker_info() unwind path tears down the already\npublished pn->shrinker_info arrays without shrinker_mutex.  The\nexpand_one_shrinker_info() can race with that teardown in the same way,\nleading to use-after-free or double-free of the old shrinker_info.\n\nFix this by serializing shrinker_info teardown with shrinker_mutex, and by\nkeeping alloc_shrinker_info() error cleanup inside the locked section.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:25","updated_at":"2026-07-27 05:16:48"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/284c267f013e45d8c89d9fb9373105dc8e6c0947","name":"https://git.kernel.org/stable/c/284c267f013e45d8c89d9fb9373105dc8e6c0947","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b9a280a9a454ed514636351d53fe2a233dc5054b","name":"https://git.kernel.org/stable/c/b9a280a9a454ed514636351d53fe2a233dc5054b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6465ff3ce65131c774a312d450abe10f4b9f3875","name":"https://git.kernel.org/stable/c/6465ff3ce65131c774a312d450abe10f4b9f3875","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/65476d31d8056e859c48580f82295ce159196ffe","name":"https://git.kernel.org/stable/c/65476d31d8056e859c48580f82295ce159196ffe","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64418","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64418","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 307bececcd1205bcb67a3c0d53a69db237ccc9d4 b9a280a9a454ed514636351d53fe2a233dc5054b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 307bececcd1205bcb67a3c0d53a69db237ccc9d4 6465ff3ce65131c774a312d450abe10f4b9f3875 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 307bececcd1205bcb67a3c0d53a69db237ccc9d4 284c267f013e45d8c89d9fb9373105dc8e6c0947 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 307bececcd1205bcb67a3c0d53a69db237ccc9d4 65476d31d8056e859c48580f82295ce159196ffe git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.7","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.96 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64418","cve":"CVE-2026-64418","epss":"0.001250000","percentile":"0.025990000","score_date":"2026-07-27","updated_at":"2026-07-28 00:07:43"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["mm/shrinker.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"b9a280a9a454ed514636351d53fe2a233dc5054b","status":"affected","version":"307bececcd1205bcb67a3c0d53a69db237ccc9d4","versionType":"git"},{"lessThan":"6465ff3ce65131c774a312d450abe10f4b9f3875","status":"affected","version":"307bececcd1205bcb67a3c0d53a69db237ccc9d4","versionType":"git"},{"lessThan":"284c267f013e45d8c89d9fb9373105dc8e6c0947","status":"affected","version":"307bececcd1205bcb67a3c0d53a69db237ccc9d4","versionType":"git"},{"lessThan":"65476d31d8056e859c48580f82295ce159196ffe","status":"affected","version":"307bececcd1205bcb67a3c0d53a69db237ccc9d4","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["mm/shrinker.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.7"},{"lessThan":"6.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.96","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.96","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc3","versionStartIncluding":"6.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: shrinker: fix shrinker_info teardown race with expansion\n\nexpand_shrinker_info() iterates all visible memcgs under shrinker_mutex,\nincluding memcgs that have not finished ->css_online() yet.\n\nOnce pn->shrinker_info has been published, teardown must stay serialized\nwith expand_shrinker_info() until that memcg is either fully online or no\nlonger visible to iteration.  Today alloc_shrinker_info() breaks that rule\nby dropping shrinker_mutex before freeing a partially initialized\nshrinker_info array, which may cause the following race:\n\nCPU0                   CPU1\n====                   ====\n\ncss_create\n--> list_add_tail_rcu(&css->sibling, &parent_css->children);\n    online_css\n    --> mem_cgroup_css_online\n        --> alloc_shrinker_info\n            --> alloc node0 info\n                rcu_assign_pointer(C->node0->shrinker_info, old0)\n                alloc node1 info -> FAIL -> goto err\n                mutex_unlock(shrinker_mutex)\n\n                       shrinker_alloc()\n                       --> shrinker_memcg_alloc\n                           --> mutex_lock(shrinker_mutex)\n                               expand_shrinker_info\n                               --> mem_cgroup_iter see the memcg\n                                   expand_one_shrinker_info\n                                   --> old0 = C->node0->shrinker_info\n                                       memcpy(new->unit, old0->unit, ...);\n\n                free_shrinker_info\n                --> kvfree(old0);\n\n                                       /* double free !! */\n                                       kvfree_rcu(old0, rcu);\n\nThe same problem exists later in mem_cgroup_css_online().  If\nalloc_shrinker_info() succeeds but a subsequent objcg allocation fails,\nthe free_objcg -> free_shrinker_info() unwind path tears down the already\npublished pn->shrinker_info arrays without shrinker_mutex.  The\nexpand_one_shrinker_info() can race with that teardown in the same way,\nleading to use-after-free or double-free of the old shrinker_info.\n\nFix this by serializing shrinker_info teardown with shrinker_mutex, and by\nkeeping alloc_shrinker_info() error cleanup inside the locked section."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-27T05:00:46.575Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/b9a280a9a454ed514636351d53fe2a233dc5054b"},{"url":"https://git.kernel.org/stable/c/6465ff3ce65131c774a312d450abe10f4b9f3875"},{"url":"https://git.kernel.org/stable/c/284c267f013e45d8c89d9fb9373105dc8e6c0947"},{"url":"https://git.kernel.org/stable/c/65476d31d8056e859c48580f82295ce159196ffe"}],"title":"mm: shrinker: fix shrinker_info teardown race with expansion","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64418","datePublished":"2026-07-25T08:50:57.594Z","dateReserved":"2026-07-19T15:36:31.786Z","dateUpdated":"2026-07-27T05:00:46.575Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:25","lastModifiedDate":"2026-07-27 05:16:48","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64418","Ordinal":"1","Title":"mm: shrinker: fix shrinker_info teardown race with expansion","CVE":"CVE-2026-64418","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64418","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: shrinker: fix shrinker_info teardown race with expansion\n\nexpand_shrinker_info() iterates all visible memcgs under shrinker_mutex,\nincluding memcgs that have not finished ->css_online() yet.\n\nOnce pn->shrinker_info has been published, teardown must stay serialized\nwith expand_shrinker_info() until that memcg is either fully online or no\nlonger visible to iteration.  Today alloc_shrinker_info() breaks that rule\nby dropping shrinker_mutex before freeing a partially initialized\nshrinker_info array, which may cause the following race:\n\nCPU0                   CPU1\n====                   ====\n\ncss_create\n--> list_add_tail_rcu(&css->sibling, &parent_css->children);\n    online_css\n    --> mem_cgroup_css_online\n        --> alloc_shrinker_info\n            --> alloc node0 info\n                rcu_assign_pointer(C->node0->shrinker_info, old0)\n                alloc node1 info -> FAIL -> goto err\n                mutex_unlock(shrinker_mutex)\n\n                       shrinker_alloc()\n                       --> shrinker_memcg_alloc\n                           --> mutex_lock(shrinker_mutex)\n                               expand_shrinker_info\n                               --> mem_cgroup_iter see the memcg\n                                   expand_one_shrinker_info\n                                   --> old0 = C->node0->shrinker_info\n                                       memcpy(new->unit, old0->unit, ...);\n\n                free_shrinker_info\n                --> kvfree(old0);\n\n                                       /* double free !! */\n                                       kvfree_rcu(old0, rcu);\n\nThe same problem exists later in mem_cgroup_css_online().  If\nalloc_shrinker_info() succeeds but a subsequent objcg allocation fails,\nthe free_objcg -> free_shrinker_info() unwind path tears down the already\npublished pn->shrinker_info arrays without shrinker_mutex.  The\nexpand_one_shrinker_info() can race with that teardown in the same way,\nleading to use-after-free or double-free of the old shrinker_info.\n\nFix this by serializing shrinker_info teardown with shrinker_mutex, and by\nkeeping alloc_shrinker_info() error cleanup inside the locked section.","Type":"Description","Title":"mm: shrinker: fix shrinker_info teardown race with expansion"}]}}}