| Release Date: | 2026-09-16 | |
| Impact: | Moderate | What is this? |
In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: check the data direction of a C2HData PDU
nvme_tcp_handle_c2h_data() finds the request by command id and checks
that it has a payload, but it does not check that the command asked for
data to be read. A controller that answers a write command with C2HData
therefore reaches nvme_tcp_recv_data(), where _copy_to_iter() hits
WARN_ON_ONCE(i->data_source) and returns 0. The receive path turns that
into -EFAULT and resets the controller.
No data is copied, so this is not memory corruption. What a controller
gets is a kernel warning it can raise at will, which is fatal on a host
booted with panic_on_warn.
The send path already knows the direction - it consults rq_data_dir()
when it builds a command - and nvme_tcp_handle_r2t() checks the length
and the offset of the request it names. The C2HData path does not check
the direction at all.
Reject a C2HData PDU whose command is not a read. Rejecting it fails
the command and resets the controller, as the neighbouring check in this
function does; what goes away is the warning.
[ 6.885580] ------------[ cut here ]------------
[ 6.886457] WARNING: lib/iov_iter.c:193 at _copy_to_iter+0x289/0x1330, CPU#0: kworker/0:1H/71
[ 6.888137] CPU: 0 UID: 0 PID: 71 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMETCP-gf5098b6bae76 #1 PREEMPT(lazy)
[ 6.891165] Workqueue: nvme_tcp_wq nvme_tcp_io_work
[ 6.891875] RIP: 0010:_copy_to_iter+0x289/0x1330
[ 6.903739] Call Trace:
[ 6.904085]
See more information about CVE-2026-89973 from MITRE CVE dictionary and NIST NVD
NOTE: The following CVSS metrics and score provided are preliminary and subject to review.
| Base Score: | 9.8 |
| Vector String: | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Version: | 3.1 |
| Attack Vector: | Network |
| Attack Complexity: | Low |
| Privileges Required: | None |
| User Interaction: | None |
| Scope: | Unchanged |
| Confidentiality Impact: | High |
| Integrity Impact: | High |
| Availability Impact: | High |
| Platform | Errata | Release Date |
| Oracle Linux version 9 (kernel-uek) | ELSA-2026-500374 | 2026-10-07 |
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