Critical severity · published Sep 11, 2026
CVE-2026-89558
md/raid10: fix still_degraded being inverted in raid10_sync_request()
9.8
CVSS
0.6%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved: md/raid10: fix still_degraded being inverted in raid10_sync_request() Commit fe6a19d40ceb ("md/md-bitmap: merge md_bitmap_start_sync() into bitmap_operations") converted still_degraded from int to bool, but inverted the assignment in the loop that checks whether the array will still be degraded after the current device is recovered: "still_degraded = 1" became "still_degraded = false". As a result, recovering a device while another mirror is still missing calls md_bitmap_start_sync() with degraded == false, which clears bitmap bits that the still-missing device needs. When that device is re-added, its bitmap-based recovery finds the bits already cleared and skips every region written while the array was degraded, so it is marked In_sync while holding stale data: silent corruption. Reproducer (raid10 near=2, 4 disks, internal bitmap): - fail and remove one disk of each mirror pair - write to the degraded array - re-add both disks and let recovery finish - "check" reports mismatch_cnt=262272 after 256 MiB of degraded writes and file contents differ; the second disk's "recovery" completes in milliseconds because everything is skipped The same conversion in raid1 got it right (still_degraded = true). Restore the correct value.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 50% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
fe6a19d40ceb44281905485f56dda715e3214e0e before 9bb8da6ecb330a5b1ac9b96f1e55f134a7aef1d4; fe6a19d40ceb44281905485f56dda715e3214e0e before 0efabe6229dc683dbf6eeebd0f9fddc7971ed420; fe6a19d40ceb44281905485f56dda715e3214e0e before 00449d752bee9c8787f42ea1bf533a9fb17f9b6b; fe6a19d40ceb44281905485f56dda715e3214e0e before 47f1441b281decde6954a2fa82b4131637d685ac; 6.12 · source: vendor
Affected product
LI
Linux
Linux
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