Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-09-11T00:00:00 kernel: nvme-tcp: fix host memory disclosure on R2T for a read command 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N CWE-201

In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: fix host memory disclosure on R2T for a read command nvme_tcp_handle_r2t() does not check the direction of the request the R2T refers to. A malicious controller can send an R2T for a READ and the host will answer it: nvme_tcp_setup_h2c_data_pdu() builds the H2CData header and nvme_tcp_try_send_data() sends the request's data buffer. That buffer is the READ destination, so its contents go to the controller. The command then completes normally and nothing is logged. Against a test controller that answers every READ with an R2T, a 4096 byte buffered read returned all 4096 bytes, split over two R2Ts. The pages contained stale kernel data, including an array of struct page pointers. Reject an R2T for a request that is not a write.

A flaw was found in the Linux kernel's NVMe (Non-Volatile Memory Express) over TCP (nvme-tcp) component. A malicious NVMe controller can exploit this vulnerability by sending a Ready to Transfer (R2T) command for a read request. The host system, failing to properly validate the request direction, will then send the contents of its read destination buffer to the controller. This can lead to the disclosure of stale kernel memory data, potentially revealing sensitive information.

Prevent the nvme-tcp kernel module from loading if NVMe over TCP storage is not required on the system. 1. Add an entry to /etc/modprobe.d to prevent the module from loading: # echo "install nvme-tcp /bin/true" >> /etc/modprobe.d/disable-nvme-tcp.conf 2. If the module is currently loaded and not in use by any storage target, unload it: # modprobe -r nvme-tcp Caveats: Disabling this module prevents the system from connecting to NVMe over TCP block storage devices. Warning: Do not attempt to unload this module if active NVMe over TCP storage is mounted or in use, as doing so will cause I/O failure and potential data loss. If the module cannot be cleanly unloaded, a system restart is required for the change to take full effect. Additionally, restrict NVMe-oF connections to verified, trusted storage targets over isolated or encrypted network fabrics. Red Hat Enterprise Linux 10 2026-09-24T00:00:00Z RHSA-2026:71602 kernel-0:6.12.0-211.60.1.el10_2 Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt Red Hat OpenShift Container Platform 4 Affected openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 4 Affected openshift/ose-rhel-coreos-9 https://www.cve.org/CVERecord?id=CVE-2026-89481 https://nvd.nist.gov/vuln/detail/CVE-2026-89481 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89481.mbox