{"id":"CVE-2026-89533","revision":"1b9fa15a26c14d8a9b963ea0aac5c725","records":[{"revision":"1b9fa15a26c14d8a9b963ea0aac5c725","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89533","aliases":[],"title":"svcrdma: Fix offset arithmetic in read_chunk_range","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Fix offset arithmetic in read_chunk_range\n\nsvc_rdma_read_chunk_range() walks a Read chunk's segment list to\nbuild a sub-range starting at byte offset and spanning length bytes\nfor a Position-Zero or Call chunk. Two arithmetic defects in the\nper-segment loop produce wrong DMA lengths and a u32 underflow:\n\n    pcl_for_each_segment(segment, chunk) {\n            if (offset > segment->rs_length) {\n                    offset -= segment->rs_length;\n                    continue;\n            }\n\n            dummy.rs_handle = segment->rs_handle;\n            dummy.rs_length = min_t(u32, length,\n                                    segment->rs_length) - offset;\n            dummy.rs_offset = segment->rs_offset + offset;\n\nFirst, the skip predicate uses '>' instead of '>='. When offset\nequals the segment's full rs_length, the segment is fully consumed\nand should be skipped, but the loop falls through into the body.\nThe resulting dummy.rs_length is min_t(u32, length, rs_length) -\nrs_length, which underflows to a near-UINT_MAX u32 when length is\nsmaller than rs_length, or is zero otherwise.\n\nSecond, the length formula subtracts offset from the min_t() result\nrather than from segment->rs_length before the cap. For offset > 0\nthe segment's residual is rs_length - offset, not rs_length, so the\ncap must be applied to the residual. With the current bracketing,\nwhenever length is smaller than rs_length - offset the per-segment\nlength becomes length - offset instead of length, silently dropping\noffset bytes from the rebuilt chunk. Combined with the boundary\ncase above it also enables the u32 underflow path, which propagates\na huge nr_bvec into svc_rdma_build_read_segment() and a multi-MiB\nkmalloc_array_node() in svc_rdma_get_rw_ctxt().\n\nAdditionally, svc_rdma_read_call_chunk() can invoke this function\nwith length == 0 when the last Read chunk ends exactly at the end\nof the Call chunk. With the corrected >= predicate, every segment\nis skipped and the function returns the initial -EINVAL, rejecting\na valid request. Return success immediately when length is zero.\nAlso break out of the loop once length is fully consumed to avoid\npassing zero-length segments to svc_rdma_build_read_segment().\n\nFix by using '>=' so a fully-consumed segment is skipped, by\nmoving '- offset' inside min_t() so the cap is applied to the\nsegment's residual length, by returning success for zero-length\nrequests, and by stopping iteration when the requested range has\nbeen consumed.","state":0,"publishedAt":"2026-09-11T19:44:12.236+00:00","modifiedAt":"2026-10-19T08:48:24.875+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sunrpc/xprtrdma/svc_rdma_rw.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"d7cc73972661be4a02a1b09f1d9b3283c6c05154\",\n                            \"lessThan\": \"10873311f91db9454e2fadbf9866bc819e0646d9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7cc73972661be4a02a1b09f1d9b3283c6c05154\",\n                            \"lessThan\": \"addbf02dfe3b25e7e38e03bbd4e2a6ed86a14be7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7cc73972661be4a02a1b09f1d9b3283c6c05154\",\n                            \"lessThan\": \"cba8543c18cf42fd80fd63effb6df6ff4f7e73ce\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7cc73972661be4a02a1b09f1d9b3283c6c05154\",\n                            \"lessThan\": \"6ee4dc7476b3abc92ec1d444533a559f33f59561\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7cc73972661be4a02a1b09f1d9b3283c6c05154\",\n                            \"lessThan\": \"a46b35f213c2426f5d6a0458a8f7e873fc59cdfd\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7cc73972661be4a02a1b09f1d9b3283c6c05154\",\n                            \"lessThan\": \"4493c96bbd0068fadf69cbae8d13426202e34cdc\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7cc73972661be4a02a1b09f1d9b3283c6c05154\",\n                            \"lessThan\": \"4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sunrpc/xprtrdma/svc_rdma_rw.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.11\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.11\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/10873311f91db9454e2fadbf9866bc819e0646d9","https://git.kernel.org/stable/c/addbf02dfe3b25e7e38e03bbd4e2a6ed86a14be7","https://git.kernel.org/stable/c/cba8543c18cf42fd80fd63effb6df6ff4f7e73ce","https://git.kernel.org/stable/c/6ee4dc7476b3abc92ec1d444533a559f33f59561","https://git.kernel.org/stable/c/a46b35f213c2426f5d6a0458a8f7e873fc59cdfd","https://git.kernel.org/stable/c/4493c96bbd0068fadf69cbae8d13426202e34cdc","https://git.kernel.org/stable/c/4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89533","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89533","identifiers":["CVE-2026-89533"]},"retained":false,"historicalAffected":[]}],"coverage":[]}