CVE Catalog

CVE-2026-31787

High
Published: Translated: NVD NIST

Summary

A vulnerability has been identified in the Linux kernel that leads to a double free when splitting a virtual memory area (VMA). The issue occurs when a user performs a partial munmap() on a privcmd mapping, allowing for improper memory pointer management.

Risk Assessment

Double freeing memory can lead to system instability and potential security vulnerabilities that could be exploited by malicious software to gain access to memory.

Recommendation

It is recommended to update the Linux kernel to a version that includes a fix for this vulnerability to prevent the possibility of double freeing memory.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: xen/privcmd: fix double free via VMA splitting privcmd_vm_ops defines .close (privcmd_close), but neither .may_split nor .open. When userspace does a partial munmap() on a privcmd mapping, the kernel splits the VMA via __split_vma(). Since may_split is NULL, the split is allowed. vm_area_dup() copies vm_private_data (a pages array allocated in alloc_empty_pages()) into the new VMA without any fixup, because there is no .open callback. Both VMAs now point to the same pages array. When the unmapped portion is closed, privcmd_close() calls: - xen_unmap_domain_gfn_range() - xen_free_unpopulated_pages() - kvfree(pages) The surviving VMA still holds the dangling pointer. When it is later destroyed, the same sequence runs again, which leads to a double free. Fix this issue by adding a .may_split callback denying the VMA split. This is XSA-487 / CVE-2026-31787

Vulnerability data from NVD (NIST) · CISA KEV · EPSS