CVE-2026-46133 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/006a3a5f75345c6a0dbf13fd3ee01406e93b6733
https://git.kernel.org/stable/c/4c6f86d85d03cdb33addce86aa69aa795ca6c47a
https://git.kernel.org/stable/c/6fa18025e5782afff91415fd5217b39c1e4837d7
https://git.kernel.org/stable/c/e3dc3a2fb05f4ed49c7f20594c4c52350d032189
https://git.kernel.org/stable/c/f8ee926431a7bbec2b10c1290664af2cb290b983

Type	Values Removed	Values Added
Description		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.
Title		RDMA/rxe: Reject unknown opcodes before ICRC processing
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/006a3a5f75345c6a0dbf13fd3ee01406e93b6733 https://git.kernel.org/stable/c/4c6f86d85d03cdb33addce86aa69aa795ca6c47a https://git.kernel.org/stable/c/6fa18025e5782afff91415fd5217b39c1e4837d7 https://git.kernel.org/stable/c/e3dc3a2fb05f4ed49c7f20594c4c52350d032189 https://git.kernel.org/stable/c/f8ee926431a7bbec2b10c1290664af2cb290b983

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-46133", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.099Z", "datePublished": "2026-05-28T09:35:47.819Z", "dateUpdated": "2026-05-28T09:35:47.819Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-28T09:35:47.819Z"}, "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": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/infiniband/sw/rxe/rxe_recv.c"], "versions": [{"version": "8700e3e7c4857d28ebaa824509934556da0b3e76", "lessThan": "e3dc3a2fb05f4ed49c7f20594c4c52350d032189", "status": "affected", "versionType": "git"}, {"version": "8700e3e7c4857d28ebaa824509934556da0b3e76", "lessThan": "f8ee926431a7bbec2b10c1290664af2cb290b983", "status": "affected", "versionType": "git"}, {"version": "8700e3e7c4857d28ebaa824509934556da0b3e76", "lessThan": "006a3a5f75345c6a0dbf13fd3ee01406e93b6733", "status": "affected", "versionType": "git"}, {"version": "8700e3e7c4857d28ebaa824509934556da0b3e76", "lessThan": "6fa18025e5782afff91415fd5217b39c1e4837d7", "status": "affected", "versionType": "git"}, {"version": "8700e3e7c4857d28ebaa824509934556da0b3e76", "lessThan": "4c6f86d85d03cdb33addce86aa69aa795ca6c47a", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/infiniband/sw/rxe/rxe_recv.c"], "versions": [{"version": "4.8", "status": "affected"}, {"version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.140", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.88", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.30", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.7", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1-rc3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"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-rc3"}]}]}], "references": [{"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"}], "title": "RDMA/rxe: Reject unknown opcodes before ICRC processing", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"cveTags": [], "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."}], "id": "CVE-2026-46133", "lastModified": "2026-05-28T10:16:28.863", "metrics": {}, "published": "2026-05-28T10:16:28.863", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/006a3a5f75345c6a0dbf13fd3ee01406e93b6733"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4c6f86d85d03cdb33addce86aa69aa795ca6c47a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6fa18025e5782afff91415fd5217b39c1e4837d7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e3dc3a2fb05f4ed49c7f20594c4c52350d032189"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f8ee926431a7bbec2b10c1290664af2cb290b983"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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