CVE-2026-43071dcache: Limit the minimal number of bucket to two
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In the Linux kernel, the following vulnerability has been resolved: dcache: Limit the minimal number of bucket to two There is an OOB read problem on dentry_hashtable when user sets 'dhash_entries=1': BUG: unable to handle page fault for address: ffff888b30b774b0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: Oops: 0000 [#1] SMP PTI RIP: 0010:__d_lookup+0x56/0x120 Call Trace: d_lookup.cold+0x16/0x5d lookup_dcache+0x27/0xf0 lookup_one_qstr_excl+0x2a/0x180 start_dirop+0x55/0xa0 simple_start_creating+0x8d/0xa0 debugfs_start_creating+0x8c/0x180 debugfs_create_dir+0x1d/0x1c0 pinctrl_init+0x6d/0x140 do_one_initcall+0x6d/0x3d0 kernel_init_freeable+0x39f/0x460 kernel_init+0x2a/0x260 There will be only one bucket in dentry_hashtable when dhash_entries is set as one, and d_hash_shift is calculated as 32 by dcache_init(). Then, following process will access more than one buckets(which memory region is not allocated) in dentry_hashtable: d_lookup b = d_hash(hash) dentry_hashtable + ((u32)hashlen >> d_hash_shift) // The C standard defines the behavior of right shift amounts // exceeding the bit width of the operand as undefined. The // result of '(u32)hashlen >> d_hash_shift' becomes 'hashlen', // so 'b' will point to an unallocated memory region. hlist_bl_for_each_entry_rcu(b) hlist_bl_first_rcu(head) h->first // read OOB! Fix it by limiting the minimal number of dentry_hashtable bucket to two, so that 'd_hash_shift' won't exceeds the bit width of type u32.
- CVSS
- 9.1 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 builds before 45b06bb5ea96f75ad81d7ef446f832ea6b0026fe; from 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 426ef05e82ee52c8d0e95fc0808b7383d8352d73; from 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before ddd57ebce245f9c7e2f6902a6c087d6186d2385d; from 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 755b40903eff563768d4d96fd4ef51ec48adde3b; from 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 5718df131ab78897a9dd1f2e71c3ba732d4392af; from 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 277cedabb0ab86baae83fa58218be13c6d3e5526; from 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before f08fe8891c3eeb63b73f9f1f6d97aa629c821579; d4c96061fddd129778ce8b70fb093aa532f422d0; and 7 more ranges | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 3.10.55 before 3.11; from 3.12.29 before 3.13; from 3.14.19 before 3.15; from 3.16.3 before 3.17; from 3.17.1 before 6.1.175; from 6.2 before 6.6.136; from 6.7 before 6.12.83; from 6.13 before 6.18.24; and 6 more ranges | NVD |
References
- https://git.kernel.org/stable/c/45b06bb5ea96f75ad81d7ef446f832ea6b0026fepatch
- https://git.kernel.org/stable/c/426ef05e82ee52c8d0e95fc0808b7383d8352d73patch
- https://git.kernel.org/stable/c/ddd57ebce245f9c7e2f6902a6c087d6186d2385dpatch
- https://git.kernel.org/stable/c/755b40903eff563768d4d96fd4ef51ec48adde3bpatch
- https://git.kernel.org/stable/c/5718df131ab78897a9dd1f2e71c3ba732d4392afpatch
- https://git.kernel.org/stable/c/277cedabb0ab86baae83fa58218be13c6d3e5526patch
- https://git.kernel.org/stable/c/f08fe8891c3eeb63b73f9f1f6d97aa629c821579patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.