{"id":"CVE-2026-46133","summary":"RDMA/rxe: Reject unknown opcodes before ICRC processing","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Reject unknown opcodes before ICRC processing\n\nEven after applying commit 7244491dab34 (\"RDMA/rxe: Validate pad and ICRC\nbefore payload_size() in rxe_rcv\"), a single unauthenticated UDP packet\ncan still trigger panic.  That patch handled payload_size() underflow only\nfor valid opcodes with short packets, not for packets carrying an unknown\nopcode.  The unknown-opcode OOB read described below predates that commit\nand reaches back to the initial Soft RoCE driver.\n\nThe check added there reads\n\n    pkt-\u003epaylen \u003c header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE\n\nwhere header_size(pkt) expands to rxe_opcode[pkt-\u003eopcode].length.  The\nrxe_opcode[] array has 256 entries but is only populated for defined IB\nopcodes; any other entry (for example opcode 0xff) is zero-initialized, so\nlength == 0 and the check degenerates to\n\n    pkt-\u003epaylen \u003c 0 + bth_pad(pkt) + RXE_ICRC_SIZE\n\nwhich does not constrain pkt-\u003epaylen enough.  rxe_icrc_hdr() then computes\n\n    rxe_opcode[pkt-\u003eopcode].length - RXE_BTH_BYTES\n\nwhich underflows when length == 0 and passes a huge value to rxe_crc32(),\ncausing an out-of-bounds read of the skb payload.\n\nReproduced on v7.0-rc7 with that fix applied, QEMU/KVM with\nCONFIG_RDMA_RXE=y and CONFIG_KASAN=y, after\n\n    rdma link add rxe0 type rxe netdev eth0\n\nA single 48-byte UDP packet to port 4791 with BTH opcode=0xff and\nQPN=IB_MULTICAST_QPN triggers:\n\n    BUG: KASAN: slab-out-of-bounds in crc32_le+0x115/0x170\n    Read of size 1 at addr ...\n    The buggy address is located 0 bytes to the right of\n     allocated 704-byte region\n    Call Trace:\n     crc32_le+0x115/0x170\n     rxe_icrc_hdr.isra.0+0x226/0x300\n     rxe_icrc_check+0x13f/0x3a0\n     rxe_rcv+0x6e1/0x16e0\n     rxe_udp_encap_recv+0x20a/0x320\n     udp_queue_rcv_one_skb+0x7ed/0x12c0\n\nSubsequent packets with the same shape fault on unmapped memory and panic\nthe kernel.  The trigger requires only module load and \"rdma link add\"; no\nQP, no connection, and no authentication.\n\nFix this by rejecting packets whose opcode has no rxe_opcode[] entry,\ndetected via the zero mask or zero length, before any length arithmetic\nruns.","modified":"2026-07-09T18:31:23.109978321Z","published":"2026-05-28T09:35:47.819Z","related":["SUSE-SU-2026:22521-1","SUSE-SU-2026:22522-1","SUSE-SU-2026:2799-1","SUSE-SU-2026:2800-1","openSUSE-SU-2026:10954-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46133.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/006a3a5f75345c6a0dbf13fd3ee01406e93b6733"},{"type":"WEB","url":"https://git.kernel.org/stable/c/318787fa7193bd79691f2ebce4e80cb6abd0faef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4c6f86d85d03cdb33addce86aa69aa795ca6c47a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/599cfdf44c1701c581cd4a21f1e1e03f8dc3840b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6a79b1ea0fcb2c998fda6a793050f66146e9cc42"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6fa18025e5782afff91415fd5217b39c1e4837d7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e3dc3a2fb05f4ed49c7f20594c4c52350d032189"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f8ee926431a7bbec2b10c1290664af2cb290b983"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46133.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46133"},{"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":"8700e3e7c4857d28ebaa824509934556da0b3e76"},{"fixed":"318787fa7193bd79691f2ebce4e80cb6abd0faef"},{"fixed":"6a79b1ea0fcb2c998fda6a793050f66146e9cc42"},{"fixed":"599cfdf44c1701c581cd4a21f1e1e03f8dc3840b"},{"fixed":"e3dc3a2fb05f4ed49c7f20594c4c52350d032189"},{"fixed":"f8ee926431a7bbec2b10c1290664af2cb290b983"},{"fixed":"006a3a5f75345c6a0dbf13fd3ee01406e93b6733"},{"fixed":"6fa18025e5782afff91415fd5217b39c1e4837d7"},{"fixed":"4c6f86d85d03cdb33addce86aa69aa795ca6c47a"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46133.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8.0"},{"fixed":"5.10.258"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.209"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.140"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.88"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.30"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46133.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}