Linux Kernel up to 6.18.34/7.0.10 x86 mm broadcast_tlb_flush null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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9.5$0-$5k3.89

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 6.18.34/7.0.10. Affected is the function broadcast_tlb_flush of the component x86 mm. Such manipulation leads to null pointer dereference. This vulnerability is traded as CVE-2026-64229. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.34/7.0.10 and classified as very critical. Affected by this issue is the function broadcast_tlb_flush of the component x86 mm. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: x86/mm: Disable broadcast TLB flush when PCID is disabled Booting with "nopcid" clears X86_FEATURE_PCID and keeps CR4.PCIDE from being set to one. On AMD CPUs that support INVLPGB, broadcast TLB flushing remains enabled. There are two checks that decide whether the global ASID code runs, mm_global_asid() and consider_global_asid(), that key off of the X86_FEATURE_INVLPGB feature. Once an mm becomes active on more than three CPUs, consider_global_asid() assigns it a global ASID, after which flush_tlb_mm_range() takes the broadcast_tlb_flush() path using a non-zero PCID. Issuing an INVLPGB with a non-zero PCID while CR4.PCIDE is not set results in a #GP: Oops: general protection fault, kernel NULL pointer dereference 0x1: 0000 [#1] SMP NOPTI CPU: 158 UID: 0 PID: 3119 Comm: snap Not tainted 7.1.0-rc3 #1 PREEMPT(full) Hardware name: ... RIP: 0010:broadcast_tlb_flush Code: ... 89 da 48 83 c8 07 <0f> 01 fe eb 08 cc cc cc ... Call Trace: <TASK> flush_tlb_mm_range ptep_clear_flush wp_page_copy ? _raw_spin_unlock __handle_mm_fault handle_mm_fault do_user_addr_fault exc_page_fault asm_exc_page_fault All processors that support broadcast TLB invalidation also have PCID support, so it is only the "nopcid" scenario that is of concern. In this situation just disable the broadcast TLB support using the CPUID dependency support by making X86_FEATURE_INVLPGB dependent on X86_FEATURE_PCID. [ bp: Massage commit message. ]

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-64229 since 07/19/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/24/2026).

Upgrading to version 6.18.35 or 7.0.11 eliminates this vulnerability. Applying the patch fed725cace3ab1c4f7f8182e35029a603d953187/d2d6d21286719b454d5d87a8758c23d2377d88a2/44126343d58c68adaa8343fbf1c07dd20078c35e is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.35/7.0.11
Patch: fed725cace3ab1c4f7f8182e35029a603d953187/d2d6d21286719b454d5d87a8758c23d2377d88a2/44126343d58c68adaa8343fbf1c07dd20078c35e

Timelineinfo

07/19/2026 CVE reserved
07/24/2026 +5 days Advisory disclosed
07/24/2026 +0 days VulDB entry created
07/24/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64229 (🔒)
GCVE (CVE): GCVE-0-2026-64229
GCVE (VulDB): GCVE-100-382964

Entryinfo

Created: 07/24/2026 18:37
Changes: 07/24/2026 18:37 (59)
Complete: 🔍
Cache ID: 216::103

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