In the Linux kernel, the following vulnerability has been resolved:
dm: clear cloned request bio pointer when last clone bio completes
Stale rq->bio values have been observed to cause double-initialization of
cloned bios in request-based device-mapper targets, leading to
use-after-free and double-free scenarios.
One such case occurs when using dm-multipath on top of a PCIe NVMe
namespace, where cloned request bios are freed during
blk_complete_request(), but rq->bio is left intact. Subsequent clone
teardown then attempts to free the same bios again via
blk_rq_unprep_clone().
The resulting double-free path looks like:
nvme_pci_complete_batch()
nvme_complete_batch()
blk_mq_end_request_batch()
blk_complete_request() // called on a DM clone request
bio_endio() // first free of all clone bios
...
rq->end_io() // end_clone_request()
dm_complete_request(tio->orig)
dm_softirq_done()
dm_done()
dm_end_request()
blk_rq_unprep_clone() // second free of clone bios
Fix this by clearing the clone request's bio pointer when the last cloned
bio completes, ensuring that later teardown paths do not attempt to free
already-released bios.
dm: clear cloned request bio pointer when last clone bio completes
Stale rq->bio values have been observed to cause double-initialization of
cloned bios in request-based device-mapper targets, leading to
use-after-free and double-free scenarios.
One such case occurs when using dm-multipath on top of a PCIe NVMe
namespace, where cloned request bios are freed during
blk_complete_request(), but rq->bio is left intact. Subsequent clone
teardown then attempts to free the same bios again via
blk_rq_unprep_clone().
The resulting double-free path looks like:
nvme_pci_complete_batch()
nvme_complete_batch()
blk_mq_end_request_batch()
blk_complete_request() // called on a DM clone request
bio_endio() // first free of all clone bios
...
rq->end_io() // end_clone_request()
dm_complete_request(tio->orig)
dm_softirq_done()
dm_done()
dm_end_request()
blk_rq_unprep_clone() // second free of clone bios
Fix this by clearing the clone request's bio pointer when the last cloned
bio completes, ensuring that later teardown paths do not attempt to free
already-released bios.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
|
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 06 May 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: dm: clear cloned request bio pointer when last clone bio completes Stale rq->bio values have been observed to cause double-initialization of cloned bios in request-based device-mapper targets, leading to use-after-free and double-free scenarios. One such case occurs when using dm-multipath on top of a PCIe NVMe namespace, where cloned request bios are freed during blk_complete_request(), but rq->bio is left intact. Subsequent clone teardown then attempts to free the same bios again via blk_rq_unprep_clone(). The resulting double-free path looks like: nvme_pci_complete_batch() nvme_complete_batch() blk_mq_end_request_batch() blk_complete_request() // called on a DM clone request bio_endio() // first free of all clone bios ... rq->end_io() // end_clone_request() dm_complete_request(tio->orig) dm_softirq_done() dm_done() dm_end_request() blk_rq_unprep_clone() // second free of clone bios Fix this by clearing the clone request's bio pointer when the last cloned bio completes, ensuring that later teardown paths do not attempt to free already-released bios. | |
| Title | dm: clear cloned request bio pointer when last clone bio completes | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-06T11:29:00.193Z
Reserved: 2026-05-01T14:12:55.998Z
Link: CVE-2026-43278
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-05-06T12:16:49.213
Modified: 2026-05-06T12:16:49.213
Link: CVE-2026-43278
Redhat
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OpenCVE Enrichment
No data.
Weaknesses
No weakness.