{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89558","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.724Z","datePublished":"2026-09-11T19:44:30.588Z","dateUpdated":"2026-09-13T06:30:57.786Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-13T06:30:57.786Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd/raid10: fix still_degraded being inverted in raid10_sync_request()\n\nCommit fe6a19d40ceb (\"md/md-bitmap: merge md_bitmap_start_sync() into\nbitmap_operations\") converted still_degraded from int to bool, but\ninverted the assignment in the loop that checks whether the array will\nstill be degraded after the current device is recovered:\n\"still_degraded = 1\" became \"still_degraded = false\".\n\nAs a result, recovering a device while another mirror is still missing\ncalls md_bitmap_start_sync() with degraded == false, which clears bitmap\nbits that the still-missing device needs.  When that device is re-added,\nits bitmap-based recovery finds the bits already cleared and skips every\nregion written while the array was degraded, so it is marked In_sync\nwhile holding stale data: silent corruption.\n\nReproducer (raid10 near=2, 4 disks, internal bitmap):\n - fail and remove one disk of each mirror pair\n - write to the degraded array\n - re-add both disks and let recovery finish\n - \"check\" reports mismatch_cnt=262272 after 256 MiB of degraded\n   writes and file contents differ; the second disk's \"recovery\"\n   completes in milliseconds because everything is skipped\n\nThe same conversion in raid1 got it right (still_degraded = true).\nRestore the correct value."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - md RAID10 commonly backs NAS/SAN volumes exported over NFS, ksmbd, iSCSI, and NVMe-oF. Remote writes during dual-degraded operation dirty the write-intent bitmap, and after buggy recovery remote reads reach md_submit_bio()->raid10_read_request()->read_balance() and are served from the stale In_sync mirror without local shell access.\nAC:L - The inverted still_degraded assignment is deterministic in raid10_sync_request() whenever one member is recovered while another remains missing or Faulty. The documented fail/remove/write/re-add sequence needs no race or attacker-uncontrolled memory layout; write-intent bitmaps on RAID10 are a standard mdadm default, not a rare config.\nPR:N - Client I/O to an exported RAID10 LUN needs no Linux UID or host capability: unauthenticated iSCSI/NVMe-oF and guest NFS/SMB writes reach md_submit_bio() and later read stale mirrors. md ioctls/sysfs fail/re-add use capable(CAP_SYS_ADMIN), but hot-spare recovery and storage-protocol I/O do not, so Privileges Required is None rather than High.\nUI:N - No victim click, mount, or confirmation is required. The attacker or automated storage clients issue ordinary reads and writes; md_check_recovery() and md_start_sync() invoke raid10_sync_request() from hot-spare activation or disk re-add as kernel background work.\nS:U - Silent corruption, stale-data disclosure, and volume unavailability remain inside the host kernel and the md RAID10 array. The bug does not escape a VM, bypass an IOMMU, or otherwise cross a separate security authority.\nC:H - raid10_spare_active() sets In_sync on the re-added member while it still holds stale sectors. read_balance() then returns that disk's prior contents, including previously freed blocks that the current filesystem layout may assign to other users' or overwritten files, disclosing unauthorized data.\nI:H - md_bitmap_start_sync() is called with degraded=false, clearing NEEDED bits the still-missing mirror requires. That device is marked In_sync after skipping dirty regions; later read-modify-write of the stale data is mirrored to all copies, permanently corrupting filesystem and user data.\nA:H - Stale filesystem metadata served from the wrongly In_sync mirror drives remount-ro, XFS shutdown, or panic on errors=panic, and skipped bitmap recovery leaves dirty regions unrestored, denying availability of the RAID10 volume and any boot or data filesystems on it."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/raid10.c"],"versions":[{"version":"fe6a19d40ceb44281905485f56dda715e3214e0e","lessThan":"9bb8da6ecb330a5b1ac9b96f1e55f134a7aef1d4","status":"affected","versionType":"git"},{"version":"fe6a19d40ceb44281905485f56dda715e3214e0e","lessThan":"0efabe6229dc683dbf6eeebd0f9fddc7971ed420","status":"affected","versionType":"git"},{"version":"fe6a19d40ceb44281905485f56dda715e3214e0e","lessThan":"00449d752bee9c8787f42ea1bf533a9fb17f9b6b","status":"affected","versionType":"git"},{"version":"fe6a19d40ceb44281905485f56dda715e3214e0e","lessThan":"47f1441b281decde6954a2fa82b4131637d685ac","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/raid10.c"],"versions":[{"version":"6.12","status":"affected"},{"version":"0","lessThan":"6.12","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/9bb8da6ecb330a5b1ac9b96f1e55f134a7aef1d4"},{"url":"https://git.kernel.org/stable/c/0efabe6229dc683dbf6eeebd0f9fddc7971ed420"},{"url":"https://git.kernel.org/stable/c/00449d752bee9c8787f42ea1bf533a9fb17f9b6b"},{"url":"https://git.kernel.org/stable/c/47f1441b281decde6954a2fa82b4131637d685ac"}],"title":"md/raid10: fix still_degraded being inverted in raid10_sync_request()","x_generator":{"engine":"bippy-1.2.0"}}}}