Description (CNA)
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
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected d71f513985c22f1050295d1a7e4327cf9fb060da before dbf862ce9f009128ab86b234d91413a3e450beb4; affected d71f513985c22f1050295d1a7e4327cf9fb060da before 2b985d3a024b9e8c24e21671b34e855569763808; affected d71f513985c22f1050295d1a7e4327cf9fb060da before 1576ff3869cbd3620717195f971c85b7d7fd62b5; affected d71f513985c22f1050295d1a7e4327cf9fb060da before 402d84ad9e89bd4cbfd07ca8598532b7021daf95; affected d71f513985c22f1050295d1a7e4327cf9fb060da before 2894a351fe2ea8684919d36df3188b9a35e3926f; affected d71f513985c22f1050295d1a7e4327cf9fb060da before 446ee446d9ae66f36e95c3c90bbcc4e56b94cde0; affected d71f513985c22f1050295d1a7e4327cf9fb060da before 71bf829800758a6e3889096e4754ef47ba7fc850; affected d71f513985c22f1050295d1a7e4327cf9fb060da before 24daca4fc07f3ff8cd0e3f629cd982187f48436a |
| Linux / Linux | affected 3.8; unaffected 0 before 3.8; unaffected 5.10.254 through 5.10.*; unaffected 5.15.204 through 5.15.*; unaffected 6.1.170 through 6.1.*; unaffected 6.6.137 through 6.6.*; unaffected 6.12.85 through 6.12.*; unaffected 6.18.26 through 6.18.*; unaffected 7.0.3 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4
- https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808
- https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5
- https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95
- https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f
- https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0
- https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850
- https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a
ADP enrichment
No English description supplied.