PT-2026-90274 · Linux · Linux
CVE-2026-89558
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Published
2026-09-11
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Updated
2026-09-11
None
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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.
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Affected Products
Linux