CVE-2026-89480

Status: UPDATED  |  Advisory ID: CVE-2026-89480

Key Details

Affected Products, Subsystems & Sectors

What to Know

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 and shifts it on

completion, so the check must see what the completion path will see.

Only REQ_OP_READ is checked, because there the length comes from the

sectors the request covers; a passthrough command is built by its

submitter, which picks both command and buffer, so the kernel has

nothing to compare against. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References