{"id":"CVE-2026-46133","state":"PUBLISHED","title":"RDMA/rxe: Reject unknown opcodes before ICRC processing","description":"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.","publishedAt":"2026-05-28T09:35:47.819Z","updatedAt":"2026-10-19T19:36:51.685Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"318787fa7193bd79691f2ebce4e80cb6abd0faef","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"6a79b1ea0fcb2c998fda6a793050f66146e9cc42","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"599cfdf44c1701c581cd4a21f1e1e03f8dc3840b","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"e3dc3a2fb05f4ed49c7f20594c4c52350d032189","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"f8ee926431a7bbec2b10c1290664af2cb290b983","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"006a3a5f75345c6a0dbf13fd3ee01406e93b6733","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"6fa18025e5782afff91415fd5217b39c1e4837d7","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"4c6f86d85d03cdb33addce86aa69aa795ca6c47a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_recv.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.8","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.140","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.88","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.30","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.7","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_recv.c"]}],"references":["https://git.kernel.org/stable/c/318787fa7193bd79691f2ebce4e80cb6abd0faef","https://git.kernel.org/stable/c/6a79b1ea0fcb2c998fda6a793050f66146e9cc42","https://git.kernel.org/stable/c/599cfdf44c1701c581cd4a21f1e1e03f8dc3840b","https://git.kernel.org/stable/c/e3dc3a2fb05f4ed49c7f20594c4c52350d032189","https://git.kernel.org/stable/c/f8ee926431a7bbec2b10c1290664af2cb290b983","https://git.kernel.org/stable/c/006a3a5f75345c6a0dbf13fd3ee01406e93b6733","https://git.kernel.org/stable/c/6fa18025e5782afff91415fd5217b39c1e4837d7","https://git.kernel.org/stable/c/4c6f86d85d03cdb33addce86aa69aa795ca6c47a"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/46xxx/CVE-2026-46133.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46133","state":"PUBLISHED","datePublished":"2026-05-28T09:35:47.819Z","dateUpdated":"2026-10-19T19:36:51.685Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.099Z"},"containers":{"cna":{"title":"RDMA/rxe: Reject unknown opcodes before ICRC processing","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"318787fa7193bd79691f2ebce4e80cb6abd0faef","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"6a79b1ea0fcb2c998fda6a793050f66146e9cc42","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"599cfdf44c1701c581cd4a21f1e1e03f8dc3840b","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"e3dc3a2fb05f4ed49c7f20594c4c52350d032189","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"f8ee926431a7bbec2b10c1290664af2cb290b983","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"006a3a5f75345c6a0dbf13fd3ee01406e93b6733","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"6fa18025e5782afff91415fd5217b39c1e4837d7","versionType":"git"},{"version":"8700e3e7c4857d28ebaa824509934556da0b3e76","status":"affected","lessThan":"4c6f86d85d03cdb33addce86aa69aa795ca6c47a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_recv.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.8","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.140","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.88","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.30","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.7","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_recv.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/318787fa7193bd79691f2ebce4e80cb6abd0faef"},{"url":"https://git.kernel.org/stable/c/6a79b1ea0fcb2c998fda6a793050f66146e9cc42"},{"url":"https://git.kernel.org/stable/c/599cfdf44c1701c581cd4a21f1e1e03f8dc3840b"},{"url":"https://git.kernel.org/stable/c/e3dc3a2fb05f4ed49c7f20594c4c52350d032189"},{"url":"https://git.kernel.org/stable/c/f8ee926431a7bbec2b10c1290664af2cb290b983"},{"url":"https://git.kernel.org/stable/c/006a3a5f75345c6a0dbf13fd3ee01406e93b6733"},{"url":"https://git.kernel.org/stable/c/6fa18025e5782afff91415fd5217b39c1e4837d7"},{"url":"https://git.kernel.org/stable/c/4c6f86d85d03cdb33addce86aa69aa795ca6c47a"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:29:57.097Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"5.10.258"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"5.15.209"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"6.6.140"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"6.12.88"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"6.18.30"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"7.0.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.8","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-46133","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:20:11.447368Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:36:51.685Z"}}]}}}