{"api_version":"1","generated_at":"2026-05-29T23:55:46+00:00","cve":"CVE-2026-45990","urls":{"html":"https://cve.report/CVE-2026-45990","api":"https://cve.report/api/cve/CVE-2026-45990.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-45990","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-45990"},"summary":{"title":"slub: fix data loss and overflow in krealloc()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nslub: fix data loss and overflow in krealloc()\n\nCommit 2cd8231796b5 (\"mm/slub: allow to set node and align in\nk[v]realloc\") introduced the ability to force a reallocation if the\noriginal object does not satisfy new alignment or NUMA node, even when\nthe object is being shrunk.\n\nThis introduced two bugs in the reallocation fallback path:\n\n1. Data loss during NUMA migration: The jump to 'alloc_new' happens\n   before 'ks' and 'orig_size' are initialized. As a result, the\n   memcpy() in the 'alloc_new' block would copy 0 bytes into the new\n   allocation.\n\n2. Buffer overflow during shrinking: When shrinking an object while\n   forcing a new alignment, 'new_size' is smaller than the old size.\n   However, the memcpy() used the old size ('orig_size ?: ks'), leading\n   to an out-of-bounds write.\n\nThe same overflow bug exists in the kvrealloc() fallback path, where the\nold bucket size ksize(p) is copied into the new buffer without being\nbounded by the new size.\n\nA simple reproducer:\n\n\t// e.g. add to lkdtm as KREALLOC_SHRINK_OVERFLOW\n\twhile (1) {\n\t\tvoid *p = kmalloc(128, GFP_KERNEL);\n\t\tp = krealloc_node_align(p, 64, 256, GFP_KERNEL, NUMA_NO_NODE);\n\t\tkfree(p);\n\t}\n\ndemonstrates the issue:\n\n  ==================================================================\n  BUG: KFENCE: out-of-bounds write in memcpy_orig+0x68/0x130\n\n  Out-of-bounds write at 0xffff8883ad757038 (120B right of kfence-#47):\n   memcpy_orig+0x68/0x130\n   krealloc_node_align_noprof+0x1c8/0x340\n   lkdtm_KREALLOC_SHRINK_OVERFLOW+0x8c/0xc0 [lkdtm]\n   lkdtm_do_action+0x3a/0x60 [lkdtm]\n   ...\n\n  kfence-#47: 0xffff8883ad756fc0-0xffff8883ad756fff, size=64, cache=kmalloc-64\n\n  allocated by task 316 on cpu 7 at 97.680481s (0.021813s ago):\n   krealloc_node_align_noprof+0x19c/0x340\n   lkdtm_KREALLOC_SHRINK_OVERFLOW+0x8c/0xc0 [lkdtm]\n   lkdtm_do_action+0x3a/0x60 [lkdtm]\n   ...\n  ==================================================================\n\nFix it by moving the old size calculation to the top of __do_krealloc()\nand bounding all copy lengths by the new allocation size.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-27 14:17:16","updated_at":"2026-05-27 14:48:03"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/082a6d03a2d685a83a332666b500ad3966349588","name":"https://git.kernel.org/stable/c/082a6d03a2d685a83a332666b500ad3966349588","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/38387ccc0fbe38d14fb4c2ad7ee1d7404e5e59fd","name":"https://git.kernel.org/stable/c/38387ccc0fbe38d14fb4c2ad7ee1d7404e5e59fd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/550fa6b5aabb096554536ac1e3ec96b76cbb35fd","name":"https://git.kernel.org/stable/c/550fa6b5aabb096554536ac1e3ec96b76cbb35fd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-45990","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45990","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2cd8231796b5e7133b1c3d66ad7d2a3c42c97258 38387ccc0fbe38d14fb4c2ad7ee1d7404e5e59fd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2cd8231796b5e7133b1c3d66ad7d2a3c42c97258 550fa6b5aabb096554536ac1e3ec96b76cbb35fd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2cd8231796b5e7133b1c3d66ad7d2a3c42c97258 082a6d03a2d685a83a332666b500ad3966349588 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.27 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.4 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"45990","cve":"CVE-2026-45990","epss":"0.000170000","percentile":"0.043220000","score_date":"2026-05-28","updated_at":"2026-05-29 00:13:15"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["mm/slub.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"38387ccc0fbe38d14fb4c2ad7ee1d7404e5e59fd","status":"affected","version":"2cd8231796b5e7133b1c3d66ad7d2a3c42c97258","versionType":"git"},{"lessThan":"550fa6b5aabb096554536ac1e3ec96b76cbb35fd","status":"affected","version":"2cd8231796b5e7133b1c3d66ad7d2a3c42c97258","versionType":"git"},{"lessThan":"082a6d03a2d685a83a332666b500ad3966349588","status":"affected","version":"2cd8231796b5e7133b1c3d66ad7d2a3c42c97258","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["mm/slub.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.18"},{"lessThan":"6.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.27","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.27","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.4","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1-rc1","versionStartIncluding":"6.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nslub: fix data loss and overflow in krealloc()\n\nCommit 2cd8231796b5 (\"mm/slub: allow to set node and align in\nk[v]realloc\") introduced the ability to force a reallocation if the\noriginal object does not satisfy new alignment or NUMA node, even when\nthe object is being shrunk.\n\nThis introduced two bugs in the reallocation fallback path:\n\n1. Data loss during NUMA migration: The jump to 'alloc_new' happens\n   before 'ks' and 'orig_size' are initialized. As a result, the\n   memcpy() in the 'alloc_new' block would copy 0 bytes into the new\n   allocation.\n\n2. Buffer overflow during shrinking: When shrinking an object while\n   forcing a new alignment, 'new_size' is smaller than the old size.\n   However, the memcpy() used the old size ('orig_size ?: ks'), leading\n   to an out-of-bounds write.\n\nThe same overflow bug exists in the kvrealloc() fallback path, where the\nold bucket size ksize(p) is copied into the new buffer without being\nbounded by the new size.\n\nA simple reproducer:\n\n\t// e.g. add to lkdtm as KREALLOC_SHRINK_OVERFLOW\n\twhile (1) {\n\t\tvoid *p = kmalloc(128, GFP_KERNEL);\n\t\tp = krealloc_node_align(p, 64, 256, GFP_KERNEL, NUMA_NO_NODE);\n\t\tkfree(p);\n\t}\n\ndemonstrates the issue:\n\n  ==================================================================\n  BUG: KFENCE: out-of-bounds write in memcpy_orig+0x68/0x130\n\n  Out-of-bounds write at 0xffff8883ad757038 (120B right of kfence-#47):\n   memcpy_orig+0x68/0x130\n   krealloc_node_align_noprof+0x1c8/0x340\n   lkdtm_KREALLOC_SHRINK_OVERFLOW+0x8c/0xc0 [lkdtm]\n   lkdtm_do_action+0x3a/0x60 [lkdtm]\n   ...\n\n  kfence-#47: 0xffff8883ad756fc0-0xffff8883ad756fff, size=64, cache=kmalloc-64\n\n  allocated by task 316 on cpu 7 at 97.680481s (0.021813s ago):\n   krealloc_node_align_noprof+0x19c/0x340\n   lkdtm_KREALLOC_SHRINK_OVERFLOW+0x8c/0xc0 [lkdtm]\n   lkdtm_do_action+0x3a/0x60 [lkdtm]\n   ...\n  ==================================================================\n\nFix it by moving the old size calculation to the top of __do_krealloc()\nand bounding all copy lengths by the new allocation size."}],"providerMetadata":{"dateUpdated":"2026-05-27T12:55:42.572Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/38387ccc0fbe38d14fb4c2ad7ee1d7404e5e59fd"},{"url":"https://git.kernel.org/stable/c/550fa6b5aabb096554536ac1e3ec96b76cbb35fd"},{"url":"https://git.kernel.org/stable/c/082a6d03a2d685a83a332666b500ad3966349588"}],"title":"slub: fix data loss and overflow in krealloc()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-45990","datePublished":"2026-05-27T12:55:42.572Z","dateReserved":"2026-05-13T15:03:33.091Z","dateUpdated":"2026-05-27T12:55:42.572Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-27 14:17:16","lastModifiedDate":"2026-05-27 14:48:03","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"45990","Ordinal":"1","Title":"slub: fix data loss and overflow in krealloc()","CVE":"CVE-2026-45990","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"45990","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nslub: fix data loss and overflow in krealloc()\n\nCommit 2cd8231796b5 (\"mm/slub: allow to set node and align in\nk[v]realloc\") introduced the ability to force a reallocation if the\noriginal object does not satisfy new alignment or NUMA node, even when\nthe object is being shrunk.\n\nThis introduced two bugs in the reallocation fallback path:\n\n1. Data loss during NUMA migration: The jump to 'alloc_new' happens\n   before 'ks' and 'orig_size' are initialized. As a result, the\n   memcpy() in the 'alloc_new' block would copy 0 bytes into the new\n   allocation.\n\n2. Buffer overflow during shrinking: When shrinking an object while\n   forcing a new alignment, 'new_size' is smaller than the old size.\n   However, the memcpy() used the old size ('orig_size ?: ks'), leading\n   to an out-of-bounds write.\n\nThe same overflow bug exists in the kvrealloc() fallback path, where the\nold bucket size ksize(p) is copied into the new buffer without being\nbounded by the new size.\n\nA simple reproducer:\n\n\t// e.g. add to lkdtm as KREALLOC_SHRINK_OVERFLOW\n\twhile (1) {\n\t\tvoid *p = kmalloc(128, GFP_KERNEL);\n\t\tp = krealloc_node_align(p, 64, 256, GFP_KERNEL, NUMA_NO_NODE);\n\t\tkfree(p);\n\t}\n\ndemonstrates the issue:\n\n  ==================================================================\n  BUG: KFENCE: out-of-bounds write in memcpy_orig+0x68/0x130\n\n  Out-of-bounds write at 0xffff8883ad757038 (120B right of kfence-#47):\n   memcpy_orig+0x68/0x130\n   krealloc_node_align_noprof+0x1c8/0x340\n   lkdtm_KREALLOC_SHRINK_OVERFLOW+0x8c/0xc0 [lkdtm]\n   lkdtm_do_action+0x3a/0x60 [lkdtm]\n   ...\n\n  kfence-#47: 0xffff8883ad756fc0-0xffff8883ad756fff, size=64, cache=kmalloc-64\n\n  allocated by task 316 on cpu 7 at 97.680481s (0.021813s ago):\n   krealloc_node_align_noprof+0x19c/0x340\n   lkdtm_KREALLOC_SHRINK_OVERFLOW+0x8c/0xc0 [lkdtm]\n   lkdtm_do_action+0x3a/0x60 [lkdtm]\n   ...\n  ==================================================================\n\nFix it by moving the old size calculation to the top of __do_krealloc()\nand bounding all copy lengths by the new allocation size.","Type":"Description","Title":"slub: fix data loss and overflow in krealloc()"}]}}}