CVE-2026-46133
published 2026-05-28CVE-2026-46133: In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Reject unknown opcodes before ICRC processing Even after applying commit…
high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
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 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 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.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < e3dc3a2fb05f4ed49c7f20594c4c52350d032189 | e3dc3a2fb05f4ed49c7f20594c4c52350d032189 |
| linux | linux | >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < f8ee926431a7bbec2b10c1290664af2cb290b983 | f8ee926431a7bbec2b10c1290664af2cb290b983 |
| linux | linux | >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < 006a3a5f75345c6a0dbf13fd3ee01406e93b6733 | 006a3a5f75345c6a0dbf13fd3ee01406e93b6733 |
| linux | linux | >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < 6fa18025e5782afff91415fd5217b39c1e4837d7 | 6fa18025e5782afff91415fd5217b39c1e4837d7 |
| linux | linux | >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < 4c6f86d85d03cdb33addce86aa69aa795ca6c47a | 4c6f86d85d03cdb33addce86aa69aa795ca6c47a |
| linux | linux_kernel | — | — |