{"id":"CVE-2026-43071","title":"In the Linux kernel, the following vulnerability has been resolved:\n\ndcache: Limit the minimal number of bucket to two\n\nThere is an OOB read problem on dentry_hashtable when user sets\n'dhash_entries=1':\n  BUG: unable to handle page fault…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndcache: Limit the minimal number of bucket to two\n\nThere is an OOB read problem on dentry_hashtable when user sets\n'dhash_entries=1':\n  BUG: unable to handle page fault…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","cwe":["CWE-125"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 3.10.55, < 3.11","linux_kernel >= 3.12.29, < 3.13","linux_kernel >= 3.14.19, < 3.15","linux_kernel >= 3.16.3, < 3.17","linux_kernel >= 3.17.1, < 6.1.175","linux_kernel >= 6.2, < 6.6.136","linux_kernel >= 6.7, < 6.12.83","linux_kernel >= 6.13, < 6.18.24","linux_kernel >= 6.19, < 6.19.14","linux_kernel >= 7.0, < 7.0.1","linux_kernel = 3.17"],"patched":["linux_kernel 7.0.1"],"published":"2026-05-05","updated":"2026-09-08","sourceUpdated":"2026-09-08T09:18:02.470","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-43071","references":[{"url":"https://git.kernel.org/stable/c/277cedabb0ab86baae83fa58218be13c6d3e5526","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/426ef05e82ee52c8d0e95fc0808b7383d8352d73","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/45b06bb5ea96f75ad81d7ef446f832ea6b0026fe","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5718df131ab78897a9dd1f2e71c3ba732d4392af","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/755b40903eff563768d4d96fd4ef51ec48adde3b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ddd57ebce245f9c7e2f6902a6c087d6186d2385d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f08fe8891c3eeb63b73f9f1f6d97aa629c821579","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00399,"epssPercentile":0.33842,"ingestedAt":"2026-07-29T19:49:48.805Z","slug":"CVE-2026-43071","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndcache: Limit the minimal number of bucket to two\n\nThere is an OOB read problem on dentry_hashtable when user sets\n'dhash_entries=1':\n  BUG: unable to handle page fault for address: ffff888b30b774b0\n  #PF: supervisor read access in kernel mode\n  #PF: error_code(0x0000) - not-present page\n  Oops: Oops: 0000 [#1] SMP PTI\n  RIP: 0010:__d_lookup+0x56/0x120\n   Call Trace:\n    d_lookup.cold+0x16/0x5d\n    lookup_dcache+0x27/0xf0\n    lookup_one_qstr_excl+0x2a/0x180\n    start_dirop+0x55/0xa0\n    simple_start_creating+0x8d/0xa0\n    debugfs_start_creating+0x8c/0x180\n    debugfs_create_dir+0x1d/0x1c0\n    pinctrl_init+0x6d/0x140\n    do_one_initcall+0x6d/0x3d0\n    kernel_init_freeable+0x39f/0x460\n    kernel_init+0x2a/0x260\n\nThere will be only one bucket in dentry_hashtable when dhash_entries is\nset as one, and d_hash_shift is calculated as 32 by dcache_init(). Then,\nfollowing process will access more than one buckets(which memory region\nis not allocated) in dentry_hashtable:\n d_lookup\n  b = d_hash(hash)\n    dentry_hashtable + ((u32)hashlen >> d_hash_shift)\n    // The C standard defines the behavior of right shift amounts\n    // exceeding the bit width of the operand as undefined. The\n    // result of '(u32)hashlen >> d_hash_shift' becomes 'hashlen',\n    // so 'b' will point to an unallocated memory region.\n  hlist_bl_for_each_entry_rcu(b)\n   hlist_bl_first_rcu(head)\n    h->first  // read OOB!\n\nFix it by limiting the minimal number of dentry_hashtable bucket to two,\nso that 'd_hash_shift' won't exceeds the bit width of type u32.\n\n## Affected\n\n- `linux_kernel >= 3.10.55, < 3.11`\n- `linux_kernel >= 3.12.29, < 3.13`\n- `linux_kernel >= 3.14.19, < 3.15`\n- `linux_kernel >= 3.16.3, < 3.17`\n- `linux_kernel >= 3.17.1, < 6.1.175`\n- `linux_kernel >= 6.2, < 6.6.136`\n- `linux_kernel >= 6.7, < 6.12.83`\n- `linux_kernel >= 6.13, < 6.18.24`\n- `linux_kernel >= 6.19, < 6.19.14`\n- `linux_kernel >= 7.0, < 7.0.1`\n- `linux_kernel = 3.17`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.1`","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}