EUVD-2026-281021

fkie_cve-2026-34211

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, the @nyariv/sandboxjs parser contains unbounded recursion in the restOfExp function and the lispify/lispifyExpr call chain. An attacker can crash any Node.js process that parses untrusted input by supplying deeply nested expressions (e.g., ~2000 nested parentheses), causing a RangeError: Maximum call stack size exceeded that terminates the process. This vulnerability is fixed in 0.8.36.

GHSA-8pfc-jjgw-6g26 — SandboxJS: Stack overflow DoS via deeply nested expressions in recursive descent parser

Affected: npm: @nyariv/sandboxjs

## Summary

The `@nyariv/sandboxjs` parser contains unbounded recursion in the `restOfExp` function and the `lispify`/`lispifyExpr` call chain. An attacker can crash any Node.js process that parses untrusted input by supplying deeply nested expressions (e.g., ~2000 nested parentheses), causing a `RangeError: Maximum call stack size exceeded` that terminates the process.

## Details

The root cause is in `src/parser.ts`. The `restOfExp` function (line 443) iterates through expression characters, and when it encounters a closing bracket that doesn't match the expected `firstOpening`, it recursively calls itself at line 503:

```typescript // src/parser.ts:486-505 } else if (closings[char]) { // ... if (char === firstOpening) { done = true; break; } else { const skip = restOfExp(constants, part.substring(i + 1), [], char); // line 503 cache.set(skip.start - 1, skip.end); i += skip.length + 1; } } ```

Each nested bracket (`(`, `[`, `{`) adds a stack frame. There is no depth counter or limit check. The function signature has no depth parameter:

```typescript export function restOfExp( constants: IConstants, part: CodeString, tests?: RegExp[], quote?: string, firstOpening?: string, closingsTests?: RegExp[], details: restDetails = {}, ): CodeString { ```

A second unbounded recursive path exists through `lispify` → `lispTypes.get(type)` → `group` handler → `lispifyExpr` (line 672) → `lispify`, which processes parenthesized groups recursi…

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EUVD-2026-281021

fkie_cve-2026-34211

GHSA-8pfc-jjgw-6g26 — SandboxJS: Stack overflow DoS via deeply nested expressions in recursive descent parser