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.

An update of the linux package has been released.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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.
    (CVE-2026-46133)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
319599	Photon OS 5.0: Linux PHSA-2026-5.0-0862	Nessus	PhotonOS Local Security Checks	high
318769	Photon OS 4.0: Linux PHSA-2026-4.0-1028	Nessus	PhotonOS Local Security Checks	high
317626	Linux Distros Unpatched Vulnerability : CVE-2026-46133	Nessus	Misc.	high

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