Linux Kernel up to 7.0.0 dcache dcache_init out-of-bounds

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CTI Interest Score
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5.8$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13/7.0.0. This vulnerability affects the function dcache_init of the component dcache. Executing a manipulation can lead to out-of-bounds. This vulnerability is registered as CVE-2026-43071. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13/7.0.0 and classified as problematic. This vulnerability affects the function dcache_init of the component dcache. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-43071 since 05/01/2026. The exploitation appears to be difficult. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 312309 (Linux Distros Unpatched Vulnerability : CVE-2026-43071), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0.1 or 7.1-rc1 eliminates this vulnerability. Applying the patch 426ef05e82ee52c8d0e95fc0808b7383d8352d73/ddd57ebce245f9c7e2f6902a6c087d6186d2385d/755b40903eff563768d4d96fd4ef51ec48adde3b/5718df131ab78897a9dd1f2e71c3ba732d4392af/277cedabb0ab86baae83fa58218be13c6d3e5526/f08fe8891c3eeb63b73f9f1f6d97aa629c821579 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (312309) and CERT Bund (WID-SEC-2026-1385). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure Linux

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.8
VulDB Meta Temp Score: 5.8

VulDB Base Score: 2.6
VulDB Temp Score: 2.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.1
CNA Vector (Linux): 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 312309
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-43071

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.136/6.12.83/6.18.24/6.19.14/7.0.1/7.1-rc1
Patch: 426ef05e82ee52c8d0e95fc0808b7383d8352d73/ddd57ebce245f9c7e2f6902a6c087d6186d2385d/755b40903eff563768d4d96fd4ef51ec48adde3b/5718df131ab78897a9dd1f2e71c3ba732d4392af/277cedabb0ab86baae83fa58218be13c6d3e5526/f08fe8891c3eeb63b73f9f1f6d97aa629c821579

Timelineinfo

05/01/2026 CVE reserved
05/05/2026 +4 days Advisory disclosed
05/05/2026 +0 days VulDB entry created
06/08/2026 +34 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43071 (🔒)
GCVE (CVE): GCVE-0-2026-43071
GCVE (VulDB): GCVE-100-361210
CERT Bund: WID-SEC-2026-1385 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 05/05/2026 19:41
Updated: 06/08/2026 13:13
Changes: 05/05/2026 19:41 (59), 05/06/2026 11:30 (2), 05/06/2026 22:08 (7), 06/01/2026 05:21 (11), 06/08/2026 13:13 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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