CVE-2026-89578

Unknown

Last modified

CVE-2026-89578 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: dm-io: clone the source bio instead of copying its biovec For DM_IO_BIO requests, do_region() built each destination bio by walking the source bio's biovec and re-adding the pages one at a time, tracking the remaining transfer in sectors. The vector lengths are byte granular and need not be sector aligned (e.g.

Description

In the Linux kernel, the following vulnerability has been resolved: dm-io: clone the source bio instead of copying its biovec For DM_IO_BIO requests, do_region() built each destination bio by walking the source bio's biovec and re-adding the pages one at a time, tracking the remaining transfer in sectors. The vector lengths are byte granular and need not be sector aligned (e.g. a misaligned O_DIRECT buffer split across pages), so the sector-based accounting could lose a sub-sector fragment: to_sector() truncated the remainder and the outer loop spun forever submitting empty bios, hanging the I/O. There is no need to rebuild the biovec at all. The destination reads into (or writes from) exactly the same pages as the source bio, so the bio can simply clone the source's biovec with bio_alloc_clone() and remap it to the target device. The clone inherits the source's iterator and alignment, and the block layer splits it to the target's limits on submission, so the whole region maps to a single cloned bio with no manual page copying or sector accounting. This removes the per-page copy path (and its open-coded bvec dpages helpers) for bio-backed I/O and fixes the hang on misaligned direct I/O to a dm-mirror device. Page-list, vma and kmem sources keep the existing copy path.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 5ff3f74e145adc79b49668adb8de276446acf6be, < 9493ac67623d45b7d4671d2b0b4d0633c2bc2e51; >= 5ff3f74e145adc79b49668adb8de276446acf6be, < 8dc48b68d7c3e6ecaae80fc1592befb0e8603d6c; >= 5ff3f74e145adc79b49668adb8de276446acf6be, < 62dc37a819a5a5de5cba989ad9e96ee214b9253e
LinuxLinux6.18

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89578?
In the Linux kernel, the following vulnerability has been resolved: dm-io: clone the source bio instead of copying its biovec For DM_IO_BIO requests, do_region() built each destination bio by walking the source bio's biovec and re-adding the pages one at a time, tracking the remaining transfer in sectors. The vector lengths are byte granular and need not be sector aligned (e.g. a misaligned O_DIRECT buffer split across pages), so the sector-based accounting could lose a sub-sector fragment: to_sector() truncated the remainder and the outer loop spun forever submitting empty bios, hanging the I/O. There is no need to rebuild the biovec at all. The destination reads into (or writes from) exactly the same pages as the source bio, so the bio can simply clone the source's biovec with bio_alloc_clone() and remap it to the target device. The clone inherits the source's iterator and alignment, and the block layer splits it to the target's limits on submission, so the whole region maps to a single cloned bio with no manual page copying or sector accounting. This removes the per-page copy path (and its open-coded bvec dpages helpers) for bio-backed I/O and fixes the hang on misaligned direct I/O to a dm-mirror device. Page-list, vma and kmem sources keep the existing copy path.
How severe is CVE-2026-89578?
Severity scoring for CVE-2026-89578 is pending analysis.
How do I fix CVE-2026-89578?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST