{"api_version":"1","generated_at":"2026-07-28T12:20:25+00:00","cve":"CVE-2026-64368","urls":{"html":"https://cve.report/CVE-2026-64368","api":"https://cve.report/api/cve/CVE-2026-64368.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64368","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64368"},"summary":{"title":"mm/slab: do not limit zeroing to orig_size when only red zoning is enabled","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab: do not limit zeroing to orig_size when only red zoning is enabled\n\nWhen init (zeroing) on allocation is requested, for kmalloc() we\ngenerally have to zero the full object size even if a smaller size is\nrequested, in order to provide krealloc()'s __GFP_ZERO guarantees.\n\nBut if we track the requested size, krealloc() uses that information to\ndo the right thing, so we can zero only the requested size. With red\nzoning also enabled, any extra size became part of the red zone, so it\nmust not be zeroed and thus we must zero only the requested size.\n\nHowever the current check is imprecise, and will trigger also when only\nSLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking\nthe requested size). This means enabling red zoning alone can compromise\nkrealloc()'s __GFP_ZERO contract.\n\nFix this by using slub_debug_orig_size() instead, which is the exact\ncheck for whether the requested size is tracked. We don't need to care\nif red zoning is also enabled or not. Also update and expand the\ncomment accordingly.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:19","updated_at":"2026-07-27 05:16:43"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.1","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.1,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.1","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":8.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/2382971aaaef5bf85a651234c64906f59580b8be","name":"https://git.kernel.org/stable/c/2382971aaaef5bf85a651234c64906f59580b8be","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7e706d50fa119eead6376bf0ef973e8d73a96030","name":"https://git.kernel.org/stable/c/7e706d50fa119eead6376bf0ef973e8d73a96030","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/648927ceb84021a25a0fbd5673740956f318d534","name":"https://git.kernel.org/stable/c/648927ceb84021a25a0fbd5673740956f318d534","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6256899c3a34674bba6076884aedbba49fc695e4","name":"https://git.kernel.org/stable/c/6256899c3a34674bba6076884aedbba49fc695e4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0d18ccef142f04433dfb2a0c120cf223d2b8a42c","name":"https://git.kernel.org/stable/c/0d18ccef142f04433dfb2a0c120cf223d2b8a42c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64368","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64368","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 6256899c3a34674bba6076884aedbba49fc695e4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 7e706d50fa119eead6376bf0ef973e8d73a96030 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 2382971aaaef5bf85a651234c64906f59580b8be git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 0d18ccef142f04433dfb2a0c120cf223d2b8a42c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab: do not limit zeroing to orig_size when only red zoning is enabled\n\nWhen init (zeroing) on allocation is requested, for kmalloc() we\ngenerally have to zero the full object size even if a smaller size is\nrequested, in order to provide krealloc()'s __GFP_ZERO guarantees.\n\nBut if we track the requested size, krealloc() uses that information to\ndo the right thing, so we can zero only the requested size. With red\nzoning also enabled, any extra size became part of the red zone, so it\nmust not be zeroed and thus we must zero only the requested size.\n\nHowever the current check is imprecise, and will trigger also when only\nSLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking\nthe requested size). This means enabling red zoning alone can compromise\nkrealloc()'s __GFP_ZERO contract.\n\nFix this by using slub_debug_orig_size() instead, which is the exact\ncheck for whether the requested size is tracked. We don't need to care\nif red zoning is also enabled or not. Also update and expand the\ncomment accordingly."}],"metrics":[{"cvssV3_1":{"baseScore":8.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-27T04:59:59.923Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/6256899c3a34674bba6076884aedbba49fc695e4"},{"url":"https://git.kernel.org/stable/c/7e706d50fa119eead6376bf0ef973e8d73a96030"},{"url":"https://git.kernel.org/stable/c/2382971aaaef5bf85a651234c64906f59580b8be"},{"url":"https://git.kernel.org/stable/c/0d18ccef142f04433dfb2a0c120cf223d2b8a42c"},{"url":"https://git.kernel.org/stable/c/648927ceb84021a25a0fbd5673740956f318d534"}],"title":"mm/slab: do not limit zeroing to orig_size when only red zoning is enabled","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64368","datePublished":"2026-07-25T08:50:21.831Z","dateReserved":"2026-07-19T15:36:31.783Z","dateUpdated":"2026-07-27T04:59:59.923Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:19","lastModifiedDate":"2026-07-27 05:16:43","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.1,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.2,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64368","Ordinal":"1","Title":"mm/slab: do not limit zeroing to orig_size when only red zoning ","CVE":"CVE-2026-64368","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64368","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab: do not limit zeroing to orig_size when only red zoning is enabled\n\nWhen init (zeroing) on allocation is requested, for kmalloc() we\ngenerally have to zero the full object size even if a smaller size is\nrequested, in order to provide krealloc()'s __GFP_ZERO guarantees.\n\nBut if we track the requested size, krealloc() uses that information to\ndo the right thing, so we can zero only the requested size. With red\nzoning also enabled, any extra size became part of the red zone, so it\nmust not be zeroed and thus we must zero only the requested size.\n\nHowever the current check is imprecise, and will trigger also when only\nSLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking\nthe requested size). This means enabling red zoning alone can compromise\nkrealloc()'s __GFP_ZERO contract.\n\nFix this by using slub_debug_orig_size() instead, which is the exact\ncheck for whether the requested size is tracked. We don't need to care\nif red zoning is also enabled or not. Also update and expand the\ncomment accordingly.","Type":"Description","Title":"mm/slab: do not limit zeroing to orig_size when only red zoning "}]}}}