{"cve":"CVE-2026-41197","nvd":{"published":"2026-04-23T02:16:18.127","modified":"2026-06-17T10:46:18.790","status":"Deferred","description":"Noir is a Domain Specific Language for SNARK proving systems that is designed to use any ACIR compatible proving system, and Brillig is the bytecode ACIR uses for non-determinism. Noir programs can invoke external functions through foreign calls. When compiling to Brillig bytecode, the SSA instructions are processed block-by-block in `BrilligBlock::compile_block()`. When the compiler encounters an `Instruction::Call` with a `Value::ForeignFunction` target, it invokes `codegen_call()` in `brillig_call/code_gen_call.rs`, which dispatches to `convert_ssa_foreign_call()`. Before emitting the foreign call opcode, the compiler must pre-allocate memory for any array results the call will return. This happens through `allocate_external_call_results()`, which iterates over the result types. For `Type::Array` results, it delegates to `allocate_foreign_call_result_array()` to recursively allocate memory on the heap for nested arrays. The `BrilligArray` struct is the internal representation of a Noir array in Brillig IR. Its `size` field represents the semi-flattened size, the total number of memory slots the array occupies, accounting for the fact that composite types like tuples consume multiple slots per element. This size is computed by `compute_array_length()` in `brillig_block_variables.rs`. For the outer array, `allocate_external_call_results()` correctly uses `define_variable()`, which internally calls `allocate_value_with_type()`. This function applies the formula above, producing the correct semi-flattened size. However, for nested arrays, `allocate_foreign_call_result_array()` contains a bug. The pattern `Type::Array(_, nested_size)` discards the inner types with `_` and uses only `nested_size`, the semantic length of the nested array (the number of logical elements), not the semi-flattened size. For simple element types this works correctly, but for composite element types it under-allocates. Foreign calls returning nested arrays of tuples or other composite types corrupt the Brillig VM heap. Version 1.0.0-beta.19 fixes this issue.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","score":9.3},"cvss_v3":null,"cwes":["CWE-131"],"references":["https://github.com/noir-lang/noir/releases/tag/v1.0.0-beta.19","https://github.com/noir-lang/noir/security/advisories/GHSA-jj7c-x25r-r8r3"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:33:09.003606135+00:00"},"epss":{"cve":"CVE-2026-41197","score":0.00395,"percentile":0.33752,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-jj7c-x25r-r8r3","url":"https://osv.dev/vulnerability/GHSA-jj7c-x25r-r8r3","summary":"Brillig: Heap corruption in foreign call results with nested tuple arrays","modified":"2026-05-05T16:10:00.908903Z","packages":[{"ecosystem":"crates.io","name":"brillig","purl":"pkg:cargo/brillig","ranges":["<1.0.0-beta.19"],"fixed":["1.0.0-beta.19"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}