CVE-2026-64229
x86/mm: Disable broadcast TLB flush when PCID is disabled
Description
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. ]
INFO
Published Date :
July 24, 2026, 4:16 p.m.
Last Modified :
July 24, 2026, 4:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-64229
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Apply kernel patches or updates.
- Disable broadcast TLB flushing if PCID is disabled.
- Ensure X86_FEATURE_INVLPGB depends on X86_FEATURE_PCID.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64229.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64229 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64229
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64229 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64229 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 24, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4afeb0ed1753ebcad93ee3b45427ce85e9c8ec40', 'lessThan': 'fed725cace3ab1c4f7f8182e35029a603d953187', 'versionType': 'git'}, {'status': 'affected', 'version': '4afeb0ed1753ebcad93ee3b45427ce85e9c8ec40', 'lessThan': 'd2d6d21286719b454d5d87a8758c23d2377d88a2', 'versionType': 'git'}, {'status': 'affected', 'version': '4afeb0ed1753ebcad93ee3b45427ce85e9c8ec40', 'lessThan': '44126343d58c68adaa8343fbf1c07dd20078c35e', 'versionType': 'git'}], 'programFiles': ['arch/x86/kernel/cpu/cpuid-deps.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.15'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.15', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.35', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.11', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['arch/x86/kernel/cpu/cpuid-deps.c'], 'defaultStatus': 'affected'}] Added Description 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. ] Added Reference https://git.kernel.org/stable/c/44126343d58c68adaa8343fbf1c07dd20078c35e Added Reference https://git.kernel.org/stable/c/d2d6d21286719b454d5d87a8758c23d2377d88a2 Added Reference https://git.kernel.org/stable/c/fed725cace3ab1c4f7f8182e35029a603d953187