{"id":"CVE-2026-31774","summary":"io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()\n\nsqe-\u003elen is __u32 but gets stored into sr-\u003elen which is int. When\nuserspace passes sqe-\u003elen values exceeding INT_MAX (e.g. 0xFFFFFFFF),\nsr-\u003elen overflows to a negative value. This negative value propagates\nthrough the bundle recv/send path:\n\n  1. io_recv(): sel.val = sr-\u003elen (ssize_t gets -1)\n  2. io_recv_buf_select(): arg.max_len = sel-\u003eval (size_t gets\n     0xFFFFFFFFFFFFFFFF)\n  3. io_ring_buffers_peek(): buf-\u003elen is not clamped because max_len\n     is astronomically large\n  4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs()\n  5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1,\n     causing ret to increase instead of decrease, creating an\n     infinite loop that reads past the allocated iov[] array\n\nThis results in a slab-out-of-bounds read in io_bundle_nbufs() from\nthe kmalloc-64 slab, as nbufs increments past the allocated iovec\nentries.\n\n  BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160\n  Read of size 8 at addr ffff888100ae05c8 by task exp/145\n  Call Trace:\n   io_bundle_nbufs+0x128/0x160\n   io_recv_finish+0x117/0xe20\n   io_recv+0x2db/0x1160\n\nFix this by rejecting negative sr-\u003elen values early in both\nio_sendmsg_prep() and io_recvmsg_prep(). Since sqe-\u003elen is __u32,\nany value \u003e INT_MAX indicates overflow and is not a valid length.","modified":"2026-07-15T01:48:58.193972616Z","published":"2026-05-01T14:15:02.903Z","related":["SUSE-SU-2026:22099-1","SUSE-SU-2026:22112-1","SUSE-SU-2026:22117-1","SUSE-SU-2026:22127-1","SUSE-SU-2026:2482-1","SUSE-SU-2026:2591-1","openSUSE-SU-2026:20965-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31774.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1b655cd311344117d3052f6552cb20d9901c9d7c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/90ced24c500ad4e129e9e34b7e56fd7849e350b6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b948f9d5d3057b01188e36664e7c7604d1c8ecb5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c314b405dcc4d8b9041124f928f81715d6328bec"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31774.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31774"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a05d1f625c7aa681d8816bc0f10089289ad07aad"},{"fixed":"90ced24c500ad4e129e9e34b7e56fd7849e350b6"},{"fixed":"c314b405dcc4d8b9041124f928f81715d6328bec"},{"fixed":"1b655cd311344117d3052f6552cb20d9901c9d7c"},{"fixed":"b948f9d5d3057b01188e36664e7c7604d1c8ecb5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31774.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.10.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31774.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"}]}