Linux Kernel Pagemap fs/proc/task_mmu pagemap_pmd_range_thp assertion

Summaryinfo

A vulnerability has been found in Linux Kernel and classified as problematic. The impacted element is the function pagemap_pmd_range_thp of the file fs/proc/task_mmu of the component Pagemap. The manipulation leads to assertion. This vulnerability is uniquely identified as CVE-2026-72173. Local access is required to approach this attack. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel (the affected version unknown). It has been rated as problematic. This issue affects the function pagemap_pmd_range_thp of the file fs/proc/task_mmu of the component Pagemap. The manipulation with an unknown input leads to a assertion vulnerability. Using CWE to declare the problem leads to CWE-617. The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: fs/proc/task_mmu: do not warn on seeing non-migration pmd entry Patch series "mm/hmm: A fix and a selftest", v3. Patch 1 fixes a stale warning present from the time when only migration softleaf entries were supported at the PMD level. Patch 2 adds some code into hmm-tests.c which exercises the pagemap path for PMD device-private entries. This patch (of 2): pagemap_pmd_range_thp() warns if a non-present PMD is not a migration entry. This became false once device-private entries at the PMD level were added. Therefore, remove the stale migration-only assertion.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-72173 since 08/09/2026. The exploitation is known to be easy. An attack has to be approached locally. 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 08/15/2026).

Applying the patch 319caaca072adc564ac9c5357ed013909f23d5ab/cd1fc0e3c1f67c0c31dfc215e5d9b771133dedc0 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

License

• open-source

Website

• Vendor: https://www.kernel.org/

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