{"id":"CVE-2026-31787","state":"PUBLISHED","title":"xen/privcmd: fix double free via VMA splitting","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxen/privcmd: fix double free via VMA splitting\n\nprivcmd_vm_ops defines .close (privcmd_close), but neither .may_split\nnor .open. When userspace does a partial munmap() on a privcmd mapping,\nthe kernel splits the VMA via __split_vma(). Since may_split is NULL,\nthe split is allowed. vm_area_dup() copies vm_private_data (a pages\narray allocated in alloc_empty_pages()) into the new VMA without any\nfixup, because there is no .open callback.\n\nBoth VMAs now point to the same pages array. When the unmapped portion\nis closed, privcmd_close() calls:\n    - xen_unmap_domain_gfn_range()\n    - xen_free_unpopulated_pages()\n    - kvfree(pages)\n\nThe surviving VMA still holds the dangling pointer. When it is later\ndestroyed, the same sequence runs again, which leads to a double free.\n\nFix this issue by adding a .may_split callback denying the VMA split.\n\nThis is XSA-487 / CVE-2026-31787","publishedAt":"2026-04-30T10:31:28.992Z","updatedAt":"2026-06-14T17:44:41.402Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"dbf862ce9f009128ab86b234d91413a3e450beb4","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"2b985d3a024b9e8c24e21671b34e855569763808","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"1576ff3869cbd3620717195f971c85b7d7fd62b5","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"402d84ad9e89bd4cbfd07ca8598532b7021daf95","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"2894a351fe2ea8684919d36df3188b9a35e3926f","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"446ee446d9ae66f36e95c3c90bbcc4e56b94cde0","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"71bf829800758a6e3889096e4754ef47ba7fc850","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"24daca4fc07f3ff8cd0e3f629cd982187f48436a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/xen/privcmd.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.254","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.204","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.170","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.137","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.85","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.26","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.3","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/xen/privcmd.c"]}],"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","http://www.openwall.com/lists/oss-security/2026/04/28/14","http://xenbits.xen.org/xsa/advisory-487.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31787.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31787","state":"PUBLISHED","datePublished":"2026-04-30T10:31:28.992Z","dateUpdated":"2026-06-14T17:44:41.402Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.141Z"},"containers":{"cna":{"title":"xen/privcmd: fix double free via VMA splitting","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nxen/privcmd: fix double free via VMA splitting\n\nprivcmd_vm_ops defines .close (privcmd_close), but neither .may_split\nnor .open. When userspace does a partial munmap() on a privcmd mapping,\nthe kernel splits the VMA via __split_vma(). Since may_split is NULL,\nthe split is allowed. vm_area_dup() copies vm_private_data (a pages\narray allocated in alloc_empty_pages()) into the new VMA without any\nfixup, because there is no .open callback.\n\nBoth VMAs now point to the same pages array. When the unmapped portion\nis closed, privcmd_close() calls:\n    - xen_unmap_domain_gfn_range()\n    - xen_free_unpopulated_pages()\n    - kvfree(pages)\n\nThe surviving VMA still holds the dangling pointer. When it is later\ndestroyed, the same sequence runs again, which leads to a double free.\n\nFix this issue by adding a .may_split callback denying the VMA split.\n\nThis is XSA-487 / CVE-2026-31787"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"dbf862ce9f009128ab86b234d91413a3e450beb4","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"2b985d3a024b9e8c24e21671b34e855569763808","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"1576ff3869cbd3620717195f971c85b7d7fd62b5","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"402d84ad9e89bd4cbfd07ca8598532b7021daf95","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"2894a351fe2ea8684919d36df3188b9a35e3926f","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"446ee446d9ae66f36e95c3c90bbcc4e56b94cde0","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"71bf829800758a6e3889096e4754ef47ba7fc850","versionType":"git"},{"version":"d71f513985c22f1050295d1a7e4327cf9fb060da","status":"affected","lessThan":"24daca4fc07f3ff8cd0e3f629cd982187f48436a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/xen/privcmd.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.254","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.204","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.170","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.137","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.85","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.26","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.3","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/xen/privcmd.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4"},{"url":"https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808"},{"url":"https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5"},{"url":"https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95"},{"url":"https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f"},{"url":"https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0"},{"url":"https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850"},{"url":"https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-06-14T17:44:41.402Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.10.254"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.15.204"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.1.170"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.6.137"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.12.85"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.18.26"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.0.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE 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