{"id":"CVE-2026-64472","title":"vfio/mlx5: Fix racy bitfields and tighten struct layout","summary":"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…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 1dd99b8f4e143592e12e5a77e7b538bc698116cb","Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < f1db80a67da928a92ba460ede1be52d8941f46be","Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 399d806f998f7a25405fc1b97227e579aead24af","Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 7ed120b1a007bace57c461805519d70e1af44e59","Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 39d163627b51886492bf31f66cb02c94613d2287","Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < f2365a63b02ddea32e7db78b742c2503ec7b81f1","Linux 5.19"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T16:39:33.414588Z"},"published":"2026-07-25","updated":"2026-11-06","sourceUpdated":"2026-11-06T16:44:53.516Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64472","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"}],"tags":["cve.org"],"epss":0.00181,"epssPercentile":0.07708,"ingestedAt":"2026-11-06T16:57:43.167Z","slug":"CVE-2026-64472","body":"## Overview\n\nIn 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\n\n## Affected\n\n- `Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 1dd99b8f4e143592e12e5a77e7b538bc698116cb`\n- `Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < f1db80a67da928a92ba460ede1be52d8941f46be`\n- `Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 399d806f998f7a25405fc1b97227e579aead24af`\n- `Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 7ed120b1a007bace57c461805519d70e1af44e59`\n- `Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < 39d163627b51886492bf31f66cb02c94613d2287`\n- `Linux >= 61a2f1460fd03285ea34c1a235f2f50f71e13a1f < f2365a63b02ddea32e7db78b742c2503ec7b81f1`\n- `Linux 5.19`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}