CVE-2026-89558

Status: UPDATED  |  Advisory ID: CVE-2026-89558

Key Details

Affected Products, Subsystems & Sectors

What to Know

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. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References