Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-09-11T00:00:00 kernel: nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-787

In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone Commit 25e5cb780e62 ("nvme-tcp: fix possible crash in write_zeroes processing") established that blk_rq_payload_bytes() must not be read without first checking blk_rq_nr_phys_segments(), and recorded the result in nvme_tcp_setup_cmd_pdu() as req->data_len. The receive side was left as it was. The two differ for REQ_OP_WRITE_ZEROES, which has no physical segments but a non-zero blk_rq_bytes(), so setup leaves req->iter untouched while the receive gate lets a C2HData through and nvme_tcp_recv_data() copies into whatever the previous command on that tag left there. The driver-private area is zeroed only when the tag set is allocated. Reproduced with a test target that leaves a residual iterator on a tag and then sends a C2HData for a WRITE_ZEROES command on the same tag: BUG: KASAN: wild-memory-access in _copy_to_iter+0x642/0x1330 Write of size 512 at addr ffe728c2175dfa81 by task kworker/0:1H/103 CPU: 0 UID: 0 PID: 103 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMETCP-gf5098b6bae76 #1 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: nvme_tcp_wq nvme_tcp_io_work Call Trace: <TASK> dump_stack_lvl+0x53/0x70 kasan_report+0xce/0x100 ? _copy_to_iter+0x642/0x1330 kasan_check_range+0x105/0x1b0 __asan_memcpy+0x3c/0x60 _copy_to_iter+0x642/0x1330 ? __pfx_sock_has_perm+0x10/0x10 ? worker_thread+0x45b/0xd10 ? __pfx__copy_to_iter+0x10/0x10 ? _raw_spin_lock_bh+0x83/0xe0 ? __pfx__raw_spin_lock_bh+0x10/0x10 __skb_datagram_iter+0xf3/0x820 ? __pfx_simple_copy_to_iter+0x10/0x10 ? __asan_memcpy+0x3c/0x60 ? skb_copy_bits+0x58d/0x830 skb_copy_datagram_iter+0x37/0x120 nvme_tcp_recv_skb+0xa07/0x4320 ? __pfx_nvme_tcp_recv_skb+0x10/0x10 __tcp_read_sock+0x1ab/0x810 ? __pfx_nvme_tcp_recv_skb+0x10/0x10 ? __pfx_lock_sock_nested+0x10/0x10 ? __pfx___tcp_read_sock+0x10/0x10 nvme_tcp_try_recv+0x152/0x1e0 ? __pfx_nvme_tcp_try_recv+0x10/0x10 ? __pfx_mutex_unlock+0x10/0x10 nvme_tcp_io_work+0x1e4/0x6c0 ? __schedule+0x181a/0x49f0 ? __pfx_nvme_tcp_io_work+0x10/0x10 process_one_work+0x633/0x1030 Keep the blk_rq_payload_bytes() test and add req->data_len to it. The old test is what rejects a C2HData naming a tag that is no longer in flight, because blk_update_request() zeroes rq->__data_len on completion; req->data_len and req->curr_bio are driver-private and survive completion, so they cannot stand in for it. Setup initialises the iterator only when both req->curr_bio and req->data_len are set, so the gate now tests the same two.

A flaw was found in the nvme-tcp module of the Linux kernel. This vulnerability arises from improper handling of C2HData for REQ_OP_WRITE_ZEROES commands, where the system fails to adequately validate the data length. A remote attacker could exploit this by sending specially crafted C2HData, leading to a wild-memory-access. This memory corruption can cause a kernel crash, resulting in a Denial of Service (DoS) for the affected system.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 10 Affected kernel-rt 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-2026-89482 https://nvd.nist.gov/vuln/detail/CVE-2026-89482 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89482.mbox