{"id":"CVE-2026-90051","published":"2026-09-17T17:16:53.490","lastModified":"2026-09-18T18:17:39.777","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: reject non zerocopy devmem tx\n\nDevmem tcp tx doesn't work without zero-copy, however it's not currently\nenforced if NETIF_F_SG isn't present. In this case, tcp_sendmsg_locked()\nwill try the copy path and try to copy data from an iovec which consists\nof offsets into the dma-buf and would normally fail. Moreover,\nd9c56501c72fd (\"net: tcp: block mixing readable and unreadable frags\")\nrelies on that and assumes that the devmem binding is present IFF we're\nusing the zero-copy path, which can be used to mix net-iov and pages in\na single skb, and break invariants. Let's reject devmem tx without\nzero-copy.\n\nNote, the parameter check the patch is modifying is too loose, we can\ncreate an io_uring request with dmabuf_id and all ZC flags, but which\nwon't have the binding. We replace it with stricter validation.","cvssScore":7.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/125755776bc6d4dd53eaf551c87e3d460625d638","tags":[]},{"url":"https://git.kernel.org/stable/c/2151b2bcf6fcec52665f606eed20da068447f0b7","tags":[]},{"url":"https://git.kernel.org/stable/c/b04326c7927af7048fd4e730f5770cca350d0a60","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}