CVE-2026-46114
published 2026-05-28CVE-2026-46114: In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Reject non-8-byte ATOMIC_WRITE payloads atomic_write_reply() at…
high7.5CVSS 3.1
AVNACLPRNUINSUCHINAN
In the Linux kernel, the following vulnerability has been resolved:
RDMA/rxe: Reject non-8-byte ATOMIC_WRITE payloads
atomic_write_reply() at drivers/infiniband/sw/rxe/rxe_resp.c
unconditionally dereferences 8 bytes at payload_addr(pkt):
value = *(u64 *)payload_addr(pkt);
check_rkey() previously accepted an ATOMIC_WRITE request with pktlen ==
resid == 0 because the length validation only compared pktlen against
resid. A remote initiator that sets the RETH length to 0 therefore reaches
atomic_write_reply() with a zero-byte logical payload, and the responder
reads sizeof(u64) bytes from past the logical end of the packet into
skb->head tailroom, then writes those 8 bytes into the attacker's MR via
rxe_mr_do_atomic_write(). That is a remote disclosure of 4 bytes of kernel
tailroom per probe (the other 4 bytes are the packet's own trailing ICRC).
IBA oA19-28 defines ATOMIC_WRITE as exactly 8 bytes. Anything else is
protocol-invalid. Hoist a strict length check into check_rkey() so the
responder never reaches the unchecked dereference, and keep the existing
WRITE-family length logic for the normal RDMA WRITE path.
Reproduced on mainline with an unmodified rxe driver: a sustained
zero-length ATOMIC_WRITE probe repeatedly leaks adjacent skb head-buffer
bytes into the attacker's MR, including recognisable kernel strings and
partial kernel-direct-map pointer words. With this patch applied the
responder rejects the PDU and the MR stays all-zero.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 539cabb7b2d8ba70f55bba91db55faef11c2a6d7 | 539cabb7b2d8ba70f55bba91db55faef11c2a6d7 |
| linux | linux | >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < d415fce3fcde6d7aeea6c25362a395b905811452 | d415fce3fcde6d7aeea6c25362a395b905811452 |
| linux | linux | >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 105bf79a23b85cf3a761d18a4f3e10ce88526bc1 | 105bf79a23b85cf3a761d18a4f3e10ce88526bc1 |
| linux | linux | >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 7ec1ed4747f5f99f8b797bb438c5efd36079fad5 | 7ec1ed4747f5f99f8b797bb438c5efd36079fad5 |
| linux | linux | >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 1114c87aa6f195cf07da55a27b2122ae26557b26 | 1114c87aa6f195cf07da55a27b2122ae26557b26 |
| linux | linux_kernel | — | — |