High 7.8Published Apr 30, 2026

CVE-2026-31787xen/privcmd: fix double free via VMA splitting

Updated under an hour ago (Oct 27, 2026, 8:30 PM ET)

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Exploited in the last 30 days

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

CVSS: 7.8 HIGH (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Jun 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from d71f513985c22f1050295d1a7e4327cf9fb060da before dbf862ce9f009128ab86b234d91413a3e450beb4; from d71f513985c22f1050295d1a7e4327cf9fb060da before 2b985d3a024b9e8c24e21671b34e855569763808; from d71f513985c22f1050295d1a7e4327cf9fb060da before 1576ff3869cbd3620717195f971c85b7d7fd62b5; from d71f513985c22f1050295d1a7e4327cf9fb060da before 402d84ad9e89bd4cbfd07ca8598532b7021daf95; from d71f513985c22f1050295d1a7e4327cf9fb060da before 2894a351fe2ea8684919d36df3188b9a35e3926f; from d71f513985c22f1050295d1a7e4327cf9fb060da before 446ee446d9ae66f36e95c3c90bbcc4e56b94cde0; from d71f513985c22f1050295d1a7e4327cf9fb060da before 71bf829800758a6e3889096e4754ef47ba7fc850; from d71f513985c22f1050295d1a7e4327cf9fb060da before 24daca4fc07f3ff8cd0e3f629cd982187f48436a	CNA record
linux linux_kernel linux:linux_kernel	from 3.8 before 5.10.254; from 5.11 before 5.15.204; from 5.16 before 6.1.170; from 6.2 before 6.6.137; from 6.7 before 6.12.85; from 6.13 before 6.18.26; from 6.19 before 7.0.3; 7.1; and 1 more ranges	NVD

References

References

https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4	patch
https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808	patch
https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5	patch
https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95	patch
https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f	patch
https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0	patch
https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850	patch
https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a	patch
http://www.openwall.com/lists/oss-security/2026/04/28/14	mailing-list, third-party-advisory
http://xenbits.xen.org/xsa/advisory-487.html	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.