CVE-2026-64232Critical· 9.8▾ MidnightIn the Linux kernel, the following vulnerability has been resolved: block: recompute nr_integrity_segments in blk_insert_cloned_request blk_insert_cloned_request() already recomputes nr_phys_segments against the bottom queue, because "…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 53.9 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 27.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.5%
In the Linux kernel, the following vulnerability has been resolved:
block: recompute nr_integrity_segments in blk_insert_cloned_request
blk_insert_cloned_request() already recomputes nr_phys_segments against the bottom queue, because "the queue settings related to segment counting may differ from the original queue." The exact same reasoning applies to integrity segments: a stacked driver's underlying queue can have tighter virt_boundary_mask, seg_boundary_mask, or max_segment_size than the top queue, in which case blk_rq_count_integrity_sg() against the bottom queue produces a different count than the cached rq->nr_integrity_segments inherited from the source request by blk_rq_prep_clone().
When the cached count is lower than the bottom queue's actual count, blk_rq_map_integrity_sg() trips
BUG_ON(segments > rq->nr_integrity_segments);
on dispatch. The same families of stacked setups that motivated the existing nr_phys_segments recompute -- dm-multipath fanning out to nvme-rdma in particular -- can produce this.
Mirror the nr_phys_segments handling: when the request carries integrity, recompute nr_integrity_segments against the bottom queue and reject the request if it exceeds the bottom queue's max_integrity_segments. blk_rq_count_integrity_sg() and queue_max_integrity_segments() are both already available via <linux/blk-integrity.h>, which blk-mq.c includes.
This closes a latent gap in the stacking contract and brings the integrity-segment accounting in line with the existing phys-segment accounting.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.