{"id":"CVE-2026-52995","summary":"net/rds: zero per-item info buffer before handing it to visitors","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: zero per-item info buffer before handing it to visitors\n\nrds_for_each_conn_info() and rds_walk_conn_path_info() both hand a\ncaller-allocated on-stack u64 buffer to a per-connection visitor and\nthen copy the full item_len bytes back to user space via\nrds_info_copy() regardless of how much of the buffer the visitor\nactually wrote.\n\nrds_ib_conn_info_visitor() and rds6_ib_conn_info_visitor() only\nwrite a subset of their output struct when the underlying\nrds_connection is not in state RDS_CONN_UP (src/dst addr, tos, sl\nand the two GIDs via explicit memsets). Several u32 fields\n(max_send_wr, max_recv_wr, max_send_sge, rdma_mr_max, rdma_mr_size,\ncache_allocs) and the 2-byte alignment hole between sl and\ncache_allocs remain as whatever stack contents preceded the visitor\ncall and are then memcpy_to_user()'d out to user space.\n\nstruct rds_info_rdma_connection and struct rds6_info_rdma_connection\nare the only rds_info_* structs in include/uapi/linux/rds.h that are\nnot marked __attribute__((packed)), so they have a real alignment\nhole. The other info visitors (rds_conn_info_visitor,\nrds6_conn_info_visitor, rds_tcp_tc_info, ...) write all fields of\ntheir packed output struct today and are not known to be vulnerable,\nbut a future visitor that adds a conditional write-path would have\nthe same bug.\n\nReproduction on a kernel built without CONFIG_INIT_STACK_ALL_ZERO=y:\na local unprivileged user opens AF_RDS, sets SO_RDS_TRANSPORT=IB,\nbinds to a local address on an RDMA-capable netdev (rxe soft-RoCE on\nany netdev is sufficient), sendto()'s any peer on the same subnet\n(fails cleanly but installs an rds_connection in the global hash in\nRDS_CONN_CONNECTING), then calls getsockopt(SOL_RDS,\nRDS_INFO_IB_CONNECTIONS). The returned 68-byte item contains 26\nbytes of stack garbage including kernel text/data pointers:\n\n    0..7   0a 63 00 01 0a 63 00 02     src=10.99.0.1 dst=10.99.0.2\n    8..39  00 ...                      gids (memset-zeroed)\n    40..47 e0 92 a3 81 ff ff ff ff     kernel pointer (max_send_wr)\n    48..55 7f 37 b5 81 ff ff ff ff     kernel pointer (rdma_mr_max)\n    56..59 01 00 08 00                 rdma_mr_size (garbage)\n    60..61 00 00                       tos, sl\n    62..63 00 00                       alignment padding\n    64..67 18 00 00 00                 cache_allocs (garbage)\n\nFix by zeroing the per-item buffer in both rds_for_each_conn_info()\nand rds_walk_conn_path_info() before invoking the visitor. This\ncovers the IPv4/IPv6 IB visitors and hardens all current and future\nvisitors against the same class of bug.\n\nNo functional change for visitors that fully populate their output.\n\nChanges in v2:\n- retarget at the net tree (subject prefix \"[PATCH net v2]\",\n  net/rds: prefix in the title)\n- pick up Reviewed-by tags from Sharath Srinivasan and\n  Allison Henderson","modified":"2026-07-12T03:55:20.297990339Z","published":"2026-06-24T16:29:08.229Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52995.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0797b2e6901827694aa9c34c4c72118c8c97fba1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5e67cc262afb384e835c3327e9d954eeaedc6a87"},{"type":"WEB","url":"https://git.kernel.org/stable/c/81651e9d7dea1c048d2952f57632a042931d7b43"},{"type":"WEB","url":"https://git.kernel.org/stable/c/912ba2e5704fdb8bc5decda96dfc1a57838f0099"},{"type":"WEB","url":"https://git.kernel.org/stable/c/91ce1bb6e4194dc2321748f68145359dcf86e350"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b6ba93a7b71ed443c9843eb12d27ed86f1e52694"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c7cb9eed8215a790f052f49cdccf577720d2bb62"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c88eb7e8d8397a8c1db59c425332c5a30b2a1682"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52995.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52995"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ec16227e14141e4fd7ae76354c09dadfe2449d9e"},{"fixed":"81651e9d7dea1c048d2952f57632a042931d7b43"},{"fixed":"0797b2e6901827694aa9c34c4c72118c8c97fba1"},{"fixed":"5e67cc262afb384e835c3327e9d954eeaedc6a87"},{"fixed":"b6ba93a7b71ed443c9843eb12d27ed86f1e52694"},{"fixed":"c7cb9eed8215a790f052f49cdccf577720d2bb62"},{"fixed":"91ce1bb6e4194dc2321748f68145359dcf86e350"},{"fixed":"912ba2e5704fdb8bc5decda96dfc1a57838f0099"},{"fixed":"c88eb7e8d8397a8c1db59c425332c5a30b2a1682"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52995.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.30"},{"fixed":"5.10.258"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.209"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.141"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.91"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.33"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52995.json"}}],"schema_version":"1.7.5"}