{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-46133", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-46133" ], "published": "2026-05-28T09:36:53Z", "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->paylen < header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE\n\nwhere header_size(pkt) expands to rxe_opcode[pkt->opcode].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->paylen < 0 + bth_pad(pkt) + RXE_ICRC_SIZE\n\nwhich does not constrain pkt->paylen enough. rxe_icrc_hdr() then computes\n\n rxe_opcode[pkt->opcode].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.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.175", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-46133" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/318787fa7193bd79691f2ebce4e80cb6abd0faef" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6a79b1ea0fcb2c998fda6a793050f66146e9cc42" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/599cfdf44c1701c581cd4a21f1e1e03f8dc3840b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e3dc3a2fb05f4ed49c7f20594c4c52350d032189" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f8ee926431a7bbec2b10c1290664af2cb290b983" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/006a3a5f75345c6a0dbf13fd3ee01406e93b6733" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6fa18025e5782afff91415fd5217b39c1e4837d7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/4c6f86d85d03cdb33addce86aa69aa795ca6c47a" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T13:16:28Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.5, "cvss_v3_severity": "High", "scenario": "AV:N - The vulnerable code processes RoCEv2 packets encapsulated in routable UDP/IP (port 4791); a remote attacker sends a single crafted UDP packet to the host running a Soft RoCE device, with no L2 adjacency required.\nAC:L - A single 48-byte packet with opcode 0xff and QPN=IB_MULTICAST_QPN deterministically triggers the underflowed length and OOB read; there is no race and no attacker-uncontrolled memory-layout dependency.\nPR:N - The OOB read occurs during ICRC validation before any QP lookup, connection, or credential check; the commit confirms it requires \"no QP, no connection, and no authentication.\"\nUI:N - Exploitation requires only that the attacker send a packet; no victim action is needed.\nS:U - The out-of-bounds read and resulting crash occur within the kernel's own security authority; no boundary (VM/IOMMU/sandbox) is crossed.\nC:N - The out-of-bounds bytes are fed into an internal CRC32 comparison and are never returned to or observable by the attacker, so no information is disclosed.\nI:N - The vulnerability is a read-only out-of-bounds access; no kernel memory is modified.\nA:H - The underflowed length drives crc32 across far out-of-bounds memory; subsequent packets fault on unmapped pages and panic the kernel, a reliable remote denial of service." } } }