{"api_version":"1","generated_at":"2026-09-11T22:32:25+00:00","cve":"CVE-2026-89533","urls":{"html":"https://cve.report/CVE-2026-89533","api":"https://cve.report/api/cve/CVE-2026-89533.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89533","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89533"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:36","updated_at":"2026-09-11 20:19:36"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e","name":"https://git.kernel.org/stable/c/4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a46b35f213c2426f5d6a0458a8f7e873fc59cdfd","name":"https://git.kernel.org/stable/c/a46b35f213c2426f5d6a0458a8f7e873fc59cdfd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4493c96bbd0068fadf69cbae8d13426202e34cdc","name":"https://git.kernel.org/stable/c/4493c96bbd0068fadf69cbae8d13426202e34cdc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6ee4dc7476b3abc92ec1d444533a559f33f59561","name":"https://git.kernel.org/stable/c/6ee4dc7476b3abc92ec1d444533a559f33f59561","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89533","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89533","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7cc73972661be4a02a1b09f1d9b3283c6c05154 6ee4dc7476b3abc92ec1d444533a559f33f59561 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7cc73972661be4a02a1b09f1d9b3283c6c05154 a46b35f213c2426f5d6a0458a8f7e873fc59cdfd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7cc73972661be4a02a1b09f1d9b3283c6c05154 4493c96bbd0068fadf69cbae8d13426202e34cdc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7cc73972661be4a02a1b09f1d9b3283c6c05154 4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.11","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sunrpc/xprtrdma/svc_rdma_rw.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"6ee4dc7476b3abc92ec1d444533a559f33f59561","status":"affected","version":"d7cc73972661be4a02a1b09f1d9b3283c6c05154","versionType":"git"},{"lessThan":"a46b35f213c2426f5d6a0458a8f7e873fc59cdfd","status":"affected","version":"d7cc73972661be4a02a1b09f1d9b3283c6c05154","versionType":"git"},{"lessThan":"4493c96bbd0068fadf69cbae8d13426202e34cdc","status":"affected","version":"d7cc73972661be4a02a1b09f1d9b3283c6c05154","versionType":"git"},{"lessThan":"4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e","status":"affected","version":"d7cc73972661be4a02a1b09f1d9b3283c6c05154","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sunrpc/xprtrdma/svc_rdma_rw.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.11"},{"lessThan":"5.11","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.109","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"5.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-09-11T19:44:12.236Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/6ee4dc7476b3abc92ec1d444533a559f33f59561"},{"url":"https://git.kernel.org/stable/c/a46b35f213c2426f5d6a0458a8f7e873fc59cdfd"},{"url":"https://git.kernel.org/stable/c/4493c96bbd0068fadf69cbae8d13426202e34cdc"},{"url":"https://git.kernel.org/stable/c/4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e"}],"title":"svcrdma: Fix offset arithmetic in read_chunk_range","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89533","datePublished":"2026-09-11T19:44:12.236Z","dateReserved":"2026-09-11T19:38:34.720Z","dateUpdated":"2026-09-11T19:44:12.236Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:36","lastModifiedDate":"2026-09-11 20:19:36","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89533","Ordinal":"1","Title":"svcrdma: Fix offset arithmetic in read_chunk_range","CVE":"CVE-2026-89533","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89533","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"svcrdma: Fix offset arithmetic in read_chunk_range"}]}}}