{"id":"CVE-2026-46114","title":"RDMA/rxe: Reject non-8-byte ATOMIC_WRITE payloads","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Reject non-8-byte ATOMIC_WRITE payloads\n\natomic_write_reply() at drivers/infiniband/sw/rxe/rxe_resp.c\nunconditionally dereferences 8 bytes at payload_addr(pkt…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 539cabb7b2d8ba70f55bba91db55faef11c2a6d7","Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < d415fce3fcde6d7aeea6c25362a395b905811452","Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 105bf79a23b85cf3a761d18a4f3e10ce88526bc1","Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 7ec1ed4747f5f99f8b797bb438c5efd36079fad5","Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 1114c87aa6f195cf07da55a27b2122ae26557b26","Linux 6.2"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T15:19:49.222043Z"},"published":"2026-05-28","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:20:51.546Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-46114","references":[{"url":"https://git.kernel.org/stable/c/539cabb7b2d8ba70f55bba91db55faef11c2a6d7"},{"url":"https://git.kernel.org/stable/c/d415fce3fcde6d7aeea6c25362a395b905811452"},{"url":"https://git.kernel.org/stable/c/105bf79a23b85cf3a761d18a4f3e10ce88526bc1"},{"url":"https://git.kernel.org/stable/c/7ec1ed4747f5f99f8b797bb438c5efd36079fad5"},{"url":"https://git.kernel.org/stable/c/1114c87aa6f195cf07da55a27b2122ae26557b26"}],"tags":["cve.org"],"epss":0.00467,"epssPercentile":0.39006,"ingestedAt":"2026-10-16T17:24:46.707Z","slug":"CVE-2026-46114","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Reject non-8-byte ATOMIC_WRITE payloads\n\natomic_write_reply() at drivers/infiniband/sw/rxe/rxe_resp.c\nunconditionally dereferences 8 bytes at payload_addr(pkt):\n\n    value = *(u64 *)payload_addr(pkt);\n\ncheck_rkey() previously accepted an ATOMIC_WRITE request with pktlen ==\nresid == 0 because the length validation only compared pktlen against\nresid. A remote initiator that sets the RETH length to 0 therefore reaches\natomic_write_reply() with a zero-byte logical payload, and the responder\nreads sizeof(u64) bytes from past the logical end of the packet into\nskb->head tailroom, then writes those 8 bytes into the attacker's MR via\nrxe_mr_do_atomic_write(). That is a remote disclosure of 4 bytes of kernel\ntailroom per probe (the other 4 bytes are the packet's own trailing ICRC).\n\nIBA oA19-28 defines ATOMIC_WRITE as exactly 8 bytes. Anything else is\nprotocol-invalid. Hoist a strict length check into check_rkey() so the\nresponder never reaches the unchecked dereference, and keep the existing\nWRITE-family length logic for the normal RDMA WRITE path.\n\nReproduced on mainline with an unmodified rxe driver: a sustained\nzero-length ATOMIC_WRITE probe repeatedly leaks adjacent skb head-buffer\nbytes into the attacker's MR, including recognisable kernel strings and\npartial kernel-direct-map pointer words.  With this patch applied the\nresponder rejects the PDU and the MR stays all-zero.\n\n## Affected\n\n- `Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 539cabb7b2d8ba70f55bba91db55faef11c2a6d7`\n- `Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < d415fce3fcde6d7aeea6c25362a395b905811452`\n- `Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 105bf79a23b85cf3a761d18a4f3e10ce88526bc1`\n- `Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 7ec1ed4747f5f99f8b797bb438c5efd36079fad5`\n- `Linux >= 034e285f8b99062a0cf29112e1232154a6a44aa5 < 1114c87aa6f195cf07da55a27b2122ae26557b26`\n- `Linux 6.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}