Description

`yaml` is a YAML parser and serialiser for JavaScript. Parsing a YAML document with a version of `yaml` on the 1.x branch prior to 1.10.3 or on the 2.x branch prior to 2.8.3 may throw a RangeError due to a stack overflow. The node resolution/composition phase uses recursive function calls without a depth bound. An attacker who can supply YAML for parsing can trigger a `RangeError: Maximum call stack size exceeded` with a small payload (~2–10 KB). The `RangeError` is not a `YAMLParseError`, so applications that only catch YAML-specific errors will encounter an unexpected exception type. Depending on the host application's exception handling, this can fail requests or terminate the Node.js process. Flow sequences allow deep nesting with minimal bytes (2 bytes per level: one `[` and one `]`). On the default Node.js stack, approximately 1,000–5,000 levels of nesting (2–10 KB input) exhaust the call stack. The exact threshold is environment-dependent (Node.js version, stack size, call stack depth at invocation). Note: the library's `Parser` (CST phase) uses a stack-based iterative approach and is not affected. Only the compose/resolve phase uses actual call-stack recursion. All three public parsing APIs are affected: `YAML.parse()`, `YAML.parseDocument()`, and `YAML.parseAllDocuments()`. Versions 1.10.3 and 2.8.3 contain a patch.

Weaknesses 1

Affected Products 2

References 4

• github.com https://github.com/eemeli/yaml/commit/1e84ebbea7ec35011a4c61bbb820a529ee4f359b
  Patch
• github.com https://github.com/eemeli/yaml/releases/tag/v1.10.3
  Product
• github.com https://github.com/eemeli/yaml/releases/tag/v2.8.3
  Release Notes
• github.com https://github.com/eemeli/yaml/security/advisories/GHSA-48c2-rrv3-qjmp
  ExploitVendor Advisory

Remediation

• github.com https://github.com/eemeli/yaml/commit/1e84ebbea7ec35011a4c61bbb820a529ee4f359b
  Patch