{"id":"CVE-2026-64457","state":"PUBLISHED","title":"virtio_pci: fix vq info pointer lookup via wrong index","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nvirtio_pci: fix vq info pointer lookup via wrong index\n\nUnbinding a virtio balloon device:\n\n    echo virtio0 > /sys/bus/virtio/drivers/virtio_balloon/unbind\n\ntriggers a NULL pointer dereference. The dmesg says:\n\n    BUG: kernel NULL pointer dereference, address: 0000000000000008\n    [...]\n    RIP: 0010:__list_del_entry_valid_or_report+0x5/0xf0\n    Call Trace:\n    <TASK>\n    vp_del_vqs+0x121/0x230\n    remove_common+0x135/0x150\n    virtballoon_remove+0xee/0x100\n    virtio_dev_remove+0x3b/0x80\n    device_release_driver_internal+0x187/0x2c0\n    unbind_store+0xb9/0xe0\n    kernfs_fop_write_iter.llvm.11660790530567441834+0xf6/0x180\n    vfs_write+0x2a9/0x3b0\n    ksys_write+0x5c/0xd0\n    do_syscall_64+0x54/0x230\n    entry_SYSCALL_64_after_hwframe+0x29/0x31\n    [...]\n    </TASK>\n\nThe virtio_balloon device registers 5 queues (inflate, deflate, stats,\nfree_page, reporting) but only the first two are unconditional. The\nstats, free_page and reporting queues are each conditional on their\nrespective feature bits. When any of these features are absent, the\ncorresponding vqs_info entry has name == NULL, creating holes in the\narray.\n\nThe root cause is an indexing mismatch introduced when vq info storage\nwas changed to be passed as an argument. vp_find_vqs_msix() and\nvp_find_vqs_intx() store the info pointer at vp_dev->vqs[i], where 'i'\nis the caller's sparse array index. However, the virtqueue itself gets\nvq->index assigned from queue_idx, a dense index that skips NULL\nentries. When holes exist, 'i' and queue_idx diverge. Later,\nvp_del_vqs() looks up info via vp_dev->vqs[vq->index] using the dense\nindex into the sparsely-populated array, and hits NULL.\n\nFix this by storing info at vp_dev->vqs[queue_idx] instead of\nvp_dev->vqs[i], so the store index matches the lookup index\n(vq->index). Apply the fix to both the MSIX and INTX paths.","publishedAt":"2026-07-25T08:51:25.364Z","updatedAt":"2026-08-17T04:56:01.747Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"41e6dc1a10036c9f47057033f19af7e52ec464b6","versionType":"git"},{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"075bc3c779e1ea7294afabdcb7e0a49536959b28","versionType":"git"},{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"64a4c0befa77bcc01076aec9f93863ffd4ed06b7","versionType":"git"},{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"f7d380fb525c13bdd114369a1979c80c346e6abc","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio_pci_common.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.11","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio_pci_common.c"]}],"references":["https://git.kernel.org/stable/c/41e6dc1a10036c9f47057033f19af7e52ec464b6","https://git.kernel.org/stable/c/075bc3c779e1ea7294afabdcb7e0a49536959b28","https://git.kernel.org/stable/c/64a4c0befa77bcc01076aec9f93863ffd4ed06b7","https://git.kernel.org/stable/c/f7d380fb525c13bdd114369a1979c80c346e6abc"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64457.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64457","state":"PUBLISHED","datePublished":"2026-07-25T08:51:25.364Z","dateUpdated":"2026-08-17T04:56:01.747Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.789Z"},"containers":{"cna":{"title":"virtio_pci: fix vq info pointer lookup via wrong index","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nvirtio_pci: fix vq info pointer lookup via wrong index\n\nUnbinding a virtio balloon device:\n\n    echo virtio0 > /sys/bus/virtio/drivers/virtio_balloon/unbind\n\ntriggers a NULL pointer dereference. The dmesg says:\n\n    BUG: kernel NULL pointer dereference, address: 0000000000000008\n    [...]\n    RIP: 0010:__list_del_entry_valid_or_report+0x5/0xf0\n    Call Trace:\n    <TASK>\n    vp_del_vqs+0x121/0x230\n    remove_common+0x135/0x150\n    virtballoon_remove+0xee/0x100\n    virtio_dev_remove+0x3b/0x80\n    device_release_driver_internal+0x187/0x2c0\n    unbind_store+0xb9/0xe0\n    kernfs_fop_write_iter.llvm.11660790530567441834+0xf6/0x180\n    vfs_write+0x2a9/0x3b0\n    ksys_write+0x5c/0xd0\n    do_syscall_64+0x54/0x230\n    entry_SYSCALL_64_after_hwframe+0x29/0x31\n    [...]\n    </TASK>\n\nThe virtio_balloon device registers 5 queues (inflate, deflate, stats,\nfree_page, reporting) but only the first two are unconditional. The\nstats, free_page and reporting queues are each conditional on their\nrespective feature bits. When any of these features are absent, the\ncorresponding vqs_info entry has name == NULL, creating holes in the\narray.\n\nThe root cause is an indexing mismatch introduced when vq info storage\nwas changed to be passed as an argument. vp_find_vqs_msix() and\nvp_find_vqs_intx() store the info pointer at vp_dev->vqs[i], where 'i'\nis the caller's sparse array index. However, the virtqueue itself gets\nvq->index assigned from queue_idx, a dense index that skips NULL\nentries. When holes exist, 'i' and queue_idx diverge. Later,\nvp_del_vqs() looks up info via vp_dev->vqs[vq->index] using the dense\nindex into the sparsely-populated array, and hits NULL.\n\nFix this by storing info at vp_dev->vqs[queue_idx] instead of\nvp_dev->vqs[i], so the store index matches the lookup index\n(vq->index). Apply the fix to both the MSIX and INTX paths."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"41e6dc1a10036c9f47057033f19af7e52ec464b6","versionType":"git"},{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"075bc3c779e1ea7294afabdcb7e0a49536959b28","versionType":"git"},{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"64a4c0befa77bcc01076aec9f93863ffd4ed06b7","versionType":"git"},{"version":"89a1c435aec269d109ed46ca7bbb10fa8edf7ace","status":"affected","lessThan":"f7d380fb525c13bdd114369a1979c80c346e6abc","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio_pci_common.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.11","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio_pci_common.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/41e6dc1a10036c9f47057033f19af7e52ec464b6"},{"url":"https://git.kernel.org/stable/c/075bc3c779e1ea7294afabdcb7e0a49536959b28"},{"url":"https://git.kernel.org/stable/c/64a4c0befa77bcc01076aec9f93863ffd4ed06b7"},{"url":"https://git.kernel.org/stable/c/f7d380fb525c13bdd114369a1979c80c346e6abc"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:56:01.747Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}