7.8

CVE-2026-31787

xen/privcmd: fix double free via VMA splitting

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
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 3.8 < 5.10.254
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.204
Linux ≫ Linux Kernel Version >= 5.16 < 6.1.170
Linux ≫ Linux Kernel Version >= 6.2 < 6.6.137
Linux ≫ Linux Kernel Version >= 6.7 < 6.12.85
Linux ≫ Linux Kernel Version >= 6.13 < 6.18.26
Linux ≫ Linux Kernel Version >= 6.19 < 7.0.3
Linux ≫ Linux Kernel Version7.1 Updaterc1
Linux ≫ Linux Kernel Version7.1 Updaterc2
VulnDex Vulnerability Enrichment
Diese Information steht angemeldeten Benutzern zur Verfügung. Login Login
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.18% 0.08
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-415 Double Free

The product calls free() twice on the same memory address.

https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5
Patch
https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f
Patch
https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808
Patch
https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95
Patch
https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0
Patch
https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850
Patch
https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4
Patch
http://www.openwall.com/lists/oss-security/2026/04/28/14
Third Party Advisory
Mailing List
http://xenbits.xen.org/xsa/advisory-487.html
Third Party Advisory
https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a
Patch