CVE-2026-89584: block: validate user space vectors during extraction
In the Linux kernel, the following vulnerability has been resolved:
block: validate user space vectors during extraction
The bio-based drivers don't necessarily check the alignment split, and stacking block drivers don't always handle a misalignment detected after submitting the bio. Validate user vectors against the device's dmaalignment as the bio is built from the ioviter, rejecting misaligned early with -EINVAL.
Event History
Frequently Asked Questions
What systems are exposed to this issue?
Systems using affected Linux kernel block I/O paths with bio-based or stacking block drivers may be exposed when user-space I/O vectors are not aligned to the underlying device's DMA alignment requirements.
What does an attacker or triggering workload need to do?
The triggering condition is a user-space I/O vector that is misaligned for the target device's dma_alignment. The issue occurs during construction of a bio from an iov_iter, before the corrected code rejects the request with -EINVAL.
What is the mitigation if the fix cannot be deployed immediately?
The provided information does not specify a configuration workaround. Avoiding or rejecting misaligned user-space I/O vectors for devices with DMA alignment requirements may reduce exposure, but the documented resolution is kernel-side validation.