CVE-2026-89480

/// Technical description

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

nvme-tcp: reject a read that transferred too few bytes

nvme_tcp_recv_data() completes a request once the current C2HData PDU

has been consumed. Nothing compares the total bytes received against

the length the command asked for: struct nvme_tcp_request has no

receive-side counter, queue->data_remaining is per queue, and

blk_mq_end_request() completes for blk_rq_bytes(rq) unconditionally

with no residual concept anywhere above.

A controller can therefore answer a 4096-byte read with 512 bytes and

have it reported as a complete read; user space then gets 4096 bytes of

which 3584 are whatever was already in the page. I reproduced that with

a test target.

Count the bytes received and refuse to complete a successful read whose

count does not match, at the two NVME_TCP_F_DATA_SUCCESS paths and in

nvme_tcp_process_nvme_cqe(). The success test shifts req->status right

by one, because the driver keeps the wire value there an

/// 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