CVE-2026-64535

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

nvmet-tcp: Fix potential UAF when ddgst mismatch

Shivam Kumar found via vulnerability testing:

When data digest is enabled on an NVMe/TCP connection and a digest

mismatch occurs on a non-final H2C_DATA PDU during an R2T-based

data transfer, the digest error handler in nvmettcptryrecvddgst()

calls nvmetrequninit() — which performs percpurefput() on the

submission queue — but does NOT mark the command as completed. It

does not set cqe->status, does not modify rbytes_done, and does not

clear any flag. When the subsequent fatal error triggers queue

teardown, nvmettcpuninitdatain_cmds() iterates all commands,

checks nvmettcpneeddatain() for each one, and finds that the

already-uninited command still appears to need data (because

rbytesdone < transferlen and cqe->status == 0). It therefore calls

nvmetrequninit() a second time on the same command — a double

percpurefput against a single percpurefget.