CVE-2026-41197
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…
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-41197 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-41197 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-41197. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-41197 in your dependencies?
O3 detects CVE-2026-41197 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.