Linux Kernel up to 6.18.38/7.1.3 x86/mm pagetable_free memory leak

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$0-$5k1.55-

Summaryinfo

A vulnerability marked as very critical has been reported in Linux Kernel up to 6.18.38/7.1.3. The impacted element is the function pagetable_free of the component x86/mm. The manipulation leads to memory leak. This vulnerability is listed as CVE-2026-64302. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.38/7.1.3. It has been rated as very critical. This issue affects the function pagetable_free of the component x86/mm. The manipulation with an unknown input leads to a memory leak vulnerability. Using CWE to declare the problem leads to CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: x86/mm: Fix freeing of PMD-sized vmemmap pages Commit bf9e4e30f353 ("x86/mm: use pagetable_free()"), switched from freeing non-boot page tables through __free_pages() to pagetable_free(). However, the function is also called to free vmemmap pages. Given that vmemmap pages are not page tables, already the page_ptdesc(page) is wrong. But worse, pagetable_free() calls: __free_pages(page, compound_order(page)); Since vmemmap pages are not compound pages (see vmemmap_alloc_block()) -- except for HVO, which doesn't apply here -- only first page of a PMD-sized vmemmap page is freed, leaking the other ones. Fix it by properly decoupling pagetable and vmemmap freeing. free_pagetable() no longer has to mess with SECTION_INFO, as only the vmemmap is marked like that in register_page_bootmem_memmap(). The indentation in remove_pmd_table() is messed up. Fix that while touching it. Bootmem info handling will soon be fixed up. For now, handle it similar to free_pagetable(), just avoiding the ifdef. [ dhansen: changelog munging. More imperative voice ]

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-64302 since 07/19/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/25/2026). MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 6.18.39, 7.1.4 or 7.2-rc1 eliminates this vulnerability. Applying the patch add1e4112e00b619614784bf630aeebfdefa23e1/03f6ecbc446c33b38fd452cd3c494092a8116967/39406c05f8f150f1685839acd38ffdd69ff92031 is able to eliminate this problem.

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Productinfo

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Version

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Website

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: Memory leak
CWE: CWE-401 / CWE-404
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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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.39/7.1.4/7.2-rc1
Patch: add1e4112e00b619614784bf630aeebfdefa23e1/03f6ecbc446c33b38fd452cd3c494092a8116967/39406c05f8f150f1685839acd38ffdd69ff92031

Timelineinfo

07/19/2026 CVE reserved
07/25/2026 +6 days Advisory disclosed
07/25/2026 +0 days VulDB entry created
07/25/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64302 (🔒)
GCVE (CVE): GCVE-0-2026-64302
GCVE (VulDB): GCVE-100-383093

Entryinfo

Created: 07/25/2026 14:14
Changes: 07/25/2026 14:14 (59)
Complete: 🔍
Cache ID: 216::103

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