CVE-2026-43278

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.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-415 CWE-415

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.1 — 6.1.165
linux	linux_kernel	6.2 — 6.6.128
linux	linux_kernel	6.7 — 6.12.75
linux	linux_kernel	6.13 — 6.18.16
linux	linux_kernel	6.19 — 6.19.6

References

Advisories & Patches

https://git.kernel.org/stable/c/7daf279c674d515fb22a727a7bbc92aeb35c5442 https://git.kernel.org/stable/c/83d72091804600ead96dc9e9f518ea56cb4942f6 https://git.kernel.org/stable/c/8d9ddad561136f7e6a9346767bf97b4d79e38e67 https://git.kernel.org/stable/c/b1c1a2637ebd675aa2d71fee8c70da8791d73850 https://git.kernel.org/stable/c/e2e738e8dfbbf83bd2bae0467ec4420cc52da42a https://git.kernel.org/stable/c/fb8a6c18fb9a6561f7a15b58b272442b77a242dd https://git.kernel.org/stable/c/3d746b639be4b4f5cd8ce2b06aa52dc443f50edc https://git.kernel.org/stable/c/9a95b98202113045bc1a5bcb30388a500f25e050

Frequently Asked Questions

What is CVE-2026-43278? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-43278? +

CVE-2026-43278 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-43278? +

CVE-2026-43278 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-43278? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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