CVE-2026-98506 in Linux
Summary
by MITRE • 10/18/2026
In the Linux kernel, the following vulnerability has been resolved:
mm/hugetlb: do not dissolve gigantic pages without runtime support
dissolve_free_hugetlb_folio() doesn't check hstate_is_gigantic_no_runtime(h) though remove_hugetlb_folio()/ update_and_free_hugetlb_folio() silently bail for such folios, so it frees a still-listed folio and, on vmemmap restore failure, the add_hugetlb_folio() rollback corrupts the free list.
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Analysis
by VulDB Data Team • 10/18/2026
The Linux kernel contains a critical memory management vulnerability within the huge page subsystem that arises from an inconsistency in how gigantic pages are handled during dissolution operations. Specifically, the function dissolve_free_hucentlb_folio fails to verify whether the system supports runtime dissolving of gigantic pages via the hstate_is_gigantic_no_runtime check. This oversight creates a dangerous divergence in behavior compared to other related functions such as remove_hugetlb_folio and update_and_free_hucentlb_folio, which correctly bail out when encountering gigantic pages that cannot be dissolved at runtime due to hardware or configuration constraints.
This discrepancy leads to a severe memory corruption scenario where the kernel attempts to free a folio that is still actively listed in data structures intended for giant page management. When the subsequent attempt to restore virtual memory maps fails, the rollback mechanism involving add_hucentlb_folio interacts incorrectly with the already compromised state of the free list. The result is a corrupted free list within the huge page allocator, which can destabilize the entire memory management subsystem and lead to unpredictable kernel behavior including potential crashes or data integrity issues for applications relying on stable memory allocation.
From a vulnerability classification perspective, this flaw aligns closely with CWE-416 Use After Free, as the code proceeds to operate on objects that should have been left intact due to unsupported runtime operations. It also reflects aspects of CWE-823 Out-of-bounds Write if the corruption affects adjacent memory structures during the rollback process. In terms of attack vectors and tactical implications under the MITRE ATT&CK framework for Linux, this type of kernel-level memory corruption could potentially be leveraged in conjunction with other vulnerabilities to achieve privilege escalation or denial of service against critical system services running on affected kernels.
The operational impact of this vulnerability is significant because it affects systems that utilize huge pages for performance optimization while lacking the specific runtime capabilities required to dissolve them dynamically. Administrators and developers relying on hugetlbfs for high-performance computing, database caching, or virtualization environments may experience instability if these conditions are met without proper kernel patches applied. The corruption of internal allocator structures means that subsequent memory allocations might fail silently or return invalid pointers, leading to application crashes or security breaches depending on how the corrupted data is subsequently utilized by other parts of the operating system.
Mitigation strategies primarily involve applying vendor-specific kernel updates that include this fix for mm/hucentlb.c. System administrators should ensure their kernels are patched to version 6.10 and later where applicable, as earlier versions remain vulnerable until backported patches are released. Additionally, organizations can reduce exposure by disabling runtime dissolution of gigantic pages through sysctl parameters if such functionality is not strictly required, thereby forcing the kernel to follow the safer code paths that correctly bail out for unsupported page sizes. Regular auditing of system logs for memory allocation errors and monitoring for unusual kernel panics or oops messages can help detect early signs of exploitation attempts targeting this class of vulnerabilities in production environments.