{"id":"CVE-2026-64472","state":"PUBLISHED","title":"vfio/mlx5: Fix racy bitfields and tighten struct layout","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/mlx5: Fix racy bitfields and tighten struct layout\n\nBitfield operations are not atomic, they use a read-modify-write\npattern, therefore we should be careful not to pack bitfields that\ncan be concurrently updated into the same storage unit.\n\nThis split takes a binary approach: flags that are only modified\npre/post open/close remain bitfields, flags modified from user\naction, including actions that reach across to another device (ex.\nreset) use dedicated storage units.\n\nNote mlx5_vhca_page_tracker.status is relocated to fill the alignment\nhole this split exposes.\n\nBitfield justifications:\n\n  migrate_cap: written only in mlx5vf_cmd_set_migratable() at probe\n  chunk_mode: written only in mlx5vf_cmd_set_migratable() at probe\n  mig_state_cap: written only in mlx5vf_cmd_set_migratable() at probe\n\nDedicated storage units:\n\n  mdev_detach: written in the VF attach/detach event notifier\n               mlx5fv_vf_event() at runtime\n  log_active: written in mlx5vf_start_page_tracker()/\n              mlx5vf_stop_page_tracker() during runtime dirty tracking\n  deferred_reset: written in mlx5vf_state_mutex_unlock()/\n                  mlx5vf_pci_aer_reset_done() during runtime reset handling\n  is_err: set by tracker error handling and dirty-log polling at runtime\n  object_changed: set by tracker event handling and cleared by dirty-log\n                  polling at runtime","publishedAt":"2026-07-25T08:51:35.978Z","updatedAt":"2026-08-17T04:56:18.199Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"1dd99b8f4e143592e12e5a77e7b538bc698116cb","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"f1db80a67da928a92ba460ede1be52d8941f46be","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"399d806f998f7a25405fc1b97227e579aead24af","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"7ed120b1a007bace57c461805519d70e1af44e59","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"39d163627b51886492bf31f66cb02c94613d2287","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"f2365a63b02ddea32e7db78b742c2503ec7b81f1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/pci/mlx5/cmd.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","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/vfio/pci/mlx5/cmd.h"]}],"references":["https://git.kernel.org/stable/c/1dd99b8f4e143592e12e5a77e7b538bc698116cb","https://git.kernel.org/stable/c/f1db80a67da928a92ba460ede1be52d8941f46be","https://git.kernel.org/stable/c/399d806f998f7a25405fc1b97227e579aead24af","https://git.kernel.org/stable/c/7ed120b1a007bace57c461805519d70e1af44e59","https://git.kernel.org/stable/c/39d163627b51886492bf31f66cb02c94613d2287","https://git.kernel.org/stable/c/f2365a63b02ddea32e7db78b742c2503ec7b81f1"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64472.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64472","state":"PUBLISHED","datePublished":"2026-07-25T08:51:35.978Z","dateUpdated":"2026-08-17T04:56:18.199Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.790Z"},"containers":{"cna":{"title":"vfio/mlx5: Fix racy bitfields and tighten struct layout","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/mlx5: Fix racy bitfields and tighten struct layout\n\nBitfield operations are not atomic, they use a read-modify-write\npattern, therefore we should be careful not to pack bitfields that\ncan be concurrently updated into the same storage unit.\n\nThis split takes a binary approach: flags that are only modified\npre/post open/close remain bitfields, flags modified from user\naction, including actions that reach across to another device (ex.\nreset) use dedicated storage units.\n\nNote mlx5_vhca_page_tracker.status is relocated to fill the alignment\nhole this split exposes.\n\nBitfield justifications:\n\n  migrate_cap: written only in mlx5vf_cmd_set_migratable() at probe\n  chunk_mode: written only in mlx5vf_cmd_set_migratable() at probe\n  mig_state_cap: written only in mlx5vf_cmd_set_migratable() at probe\n\nDedicated storage units:\n\n  mdev_detach: written in the VF attach/detach event notifier\n               mlx5fv_vf_event() at runtime\n  log_active: written in mlx5vf_start_page_tracker()/\n              mlx5vf_stop_page_tracker() during runtime dirty tracking\n  deferred_reset: written in mlx5vf_state_mutex_unlock()/\n                  mlx5vf_pci_aer_reset_done() during runtime reset handling\n  is_err: set by tracker error handling and dirty-log polling at runtime\n  object_changed: set by tracker event handling and cleared by dirty-log\n                  polling at runtime"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"1dd99b8f4e143592e12e5a77e7b538bc698116cb","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"f1db80a67da928a92ba460ede1be52d8941f46be","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"399d806f998f7a25405fc1b97227e579aead24af","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"7ed120b1a007bace57c461805519d70e1af44e59","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"39d163627b51886492bf31f66cb02c94613d2287","versionType":"git"},{"version":"61a2f1460fd03285ea34c1a235f2f50f71e13a1f","status":"affected","lessThan":"f2365a63b02ddea32e7db78b742c2503ec7b81f1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/pci/mlx5/cmd.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","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/vfio/pci/mlx5/cmd.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/1dd99b8f4e143592e12e5a77e7b538bc698116cb"},{"url":"https://git.kernel.org/stable/c/f1db80a67da928a92ba460ede1be52d8941f46be"},{"url":"https://git.kernel.org/stable/c/399d806f998f7a25405fc1b97227e579aead24af"},{"url":"https://git.kernel.org/stable/c/7ed120b1a007bace57c461805519d70e1af44e59"},{"url":"https://git.kernel.org/stable/c/39d163627b51886492bf31f66cb02c94613d2287"},{"url":"https://git.kernel.org/stable/c/f2365a63b02ddea32e7db78b742c2503ec7b81f1"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:56:18.199Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}