Brillig: Heap corruption in foreign call results with nested tuple arrays

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.3 · 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 source

EPSS

• CVE-2026-41197: 0.40% estimated exploitation activity in the next 30 days; percentile 33.78 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description Noir programs can invoke external functions through foreign calls. When compiling to Brillig bytecode, the SSA instructions are processed block-by-block in BrilligBlock::compileblock(). When the compiler encounters an Instruction::Call with a Value::ForeignFunction target, it invokes codegencall() in brilligcall/codegencall.rs, which dispatches to convertssaforeigncall(). Before emitting the foreign call opcode, the compiler must pre-allocate memory for any array results the call will return. This happens through allocateexternalcallresults(), which iterates over the result types. For Type::Array results, it delegates to allocateforeigncallresultarray() 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…

Published by the source

21 Apr 2026, 20:16 UTC

Last modified by the source

27 Apr 2026, 16:29 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jj7c-x25r-r8r3

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# Patch Next advisory brief: CVE-2026-41197

Advisory: Brillig: Heap corruption in foreign call results with nested tuple arrays
IDs: CVE-2026-41197, GHSA-jj7c-x25r-r8r3
Record: https://patchnext.com/advisories/cve-2026-41197 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: brillig 1.0.0-beta.19. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io brillig: affected <= 1.0.0-beta.18; fixed in 1.0.0-beta.19

## Suggested inspection (read-only)
- crates.io brillig: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on brillig.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jj7c-x25r-r8r3 (GitHub-reviewed advisory GHSA-jj7c-x25r-r8r3 lists affected ranges: crates.io brillig >=0 <=1.0.0-beta.18)

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