CVE-2025-39792

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

dm: Always split write BIOs to zoned device limits

Any zoned DM target that requires zone append emulation will use the

block layer zone write plugging. In such case, DM target drivers must

not split BIOs using dm_accept_partial_bio() as doing so can potentially

lead to deadlocks with queue freeze operations. Regular write operations

used to emulate zone append operations also cannot be split by the

target driver as that would result in an invalid writen sector value

return using the BIO sector.

In order for zoned DM target drivers to avoid such incorrect BIO

splitting, we must ensure that large BIOs are split before being passed

to the map() function of the target, thus guaranteeing that the

limits for the mapped device are not exceeded.

dm-crypt and dm-flakey are the only target drivers supporting zoned

devices and using dm_accept_partial_bio().

In the case of dm-crypt, this function is used to split BIOs to the

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References