CVE-2026-46133 (GCVE-0-2026-46133)
Vulnerability from cvelistv5
Published
2026-05-28 09:35
Modified
2026-10-19 19:36
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Reject unknown opcodes before ICRC processing Even after applying commit 7244491dab34 ("RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv"), a single unauthenticated UDP packet can still trigger panic. That patch handled payload_size() underflow only for valid opcodes with short packets, not for packets carrying an unknown opcode. The unknown-opcode OOB read described below predates that commit and reaches back to the initial Soft RoCE driver. The check added there reads pkt->paylen < header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE where header_size(pkt) expands to rxe_opcode[pkt->opcode].length. The rxe_opcode[] array has 256 entries but is only populated for defined IB opcodes; any other entry (for example opcode 0xff) is zero-initialized, so length == 0 and the check degenerates to pkt->paylen < 0 + bth_pad(pkt) + RXE_ICRC_SIZE which does not constrain pkt->paylen enough. rxe_icrc_hdr() then computes rxe_opcode[pkt->opcode].length - RXE_BTH_BYTES which underflows when length == 0 and passes a huge value to rxe_crc32(), causing an out-of-bounds read of the skb payload. Reproduced on v7.0-rc7 with that fix applied, QEMU/KVM with CONFIG_RDMA_RXE=y and CONFIG_KASAN=y, after rdma link add rxe0 type rxe netdev eth0 A single 48-byte UDP packet to port 4791 with BTH opcode=0xff and QPN=IB_MULTICAST_QPN triggers: BUG: KASAN: slab-out-of-bounds in crc32_le+0x115/0x170 Read of size 1 at addr ... The buggy address is located 0 bytes to the right of allocated 704-byte region Call Trace: crc32_le+0x115/0x170 rxe_icrc_hdr.isra.0+0x226/0x300 rxe_icrc_check+0x13f/0x3a0 rxe_rcv+0x6e1/0x16e0 rxe_udp_encap_recv+0x20a/0x320 udp_queue_rcv_one_skb+0x7ed/0x12c0 Subsequent packets with the same shape fault on unmapped memory and panic the kernel. The trigger requires only module load and "rdma link add"; no QP, no connection, and no authentication. Fix this by rejecting packets whose opcode has no rxe_opcode[] entry, detected via the zero mask or zero length, before any length arithmetic runs.
References
Impacted products
Vendor Product Version
Linux Linux Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76
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          "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-\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."
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    "dateUpdated": "2026-10-19T19:36:51.685Z",
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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\u0027s 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.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"318787fa7193bd79691f2ebce4e80cb6abd0faef\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"6a79b1ea0fcb2c998fda6a793050f66146e9cc42\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"599cfdf44c1701c581cd4a21f1e1e03f8dc3840b\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"e3dc3a2fb05f4ed49c7f20594c4c52350d032189\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"f8ee926431a7bbec2b10c1290664af2cb290b983\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"006a3a5f75345c6a0dbf13fd3ee01406e93b6733\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"6fa18025e5782afff91415fd5217b39c1e4837d7\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8700e3e7c4857d28ebaa824509934556da0b3e76\", \"lessThan\": \"4c6f86d85d03cdb33addce86aa69aa795ca6c47a\", \"versionType\": \"git\"}], \"programFiles\": [\"drivers/infiniband/sw/rxe/rxe_recv.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"4.8\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"4.8\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.10.258\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.15.209\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"6.1.175\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.140\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.88\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.18.30\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.18.*\"}, {\"status\": \"unaffected\", \"version\": \"7.0.7\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"7.0.*\"}, {\"status\": \"unaffected\", \"version\": \"7.1\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"drivers/infiniband/sw/rxe/rxe_recv.c\"], \"defaultStatus\": \"affected\"}], \"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\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"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-\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.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.258\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.209\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.175\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.140\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.88\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.18.30\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"7.0.7\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"7.1\", \"versionStartIncluding\": \"4.8\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T12:29:57.097Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-46133\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-19T19:36:51.685Z\", \"dateReserved\": \"2026-05-13T15:03:33.099Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2026-05-28T09:35:47.819Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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