GHSA-v422-hmwv-36x6 — body-parser vulnerable to denial of service when invalid limit value silently disables size enforcement

Affected: npm: body-parser

### Impact

When body-parser is configured with an invalid `limit` option value, such as an unparseable string or `NaN`, `bytes.parse()` returns `null` and the request body size check is silently skipped. Applications that rely on `limit` as their primary safeguard against oversized request bodies will accept arbitrarily large payloads, leading to excessive memory and CPU usage and denial of service.

This issue affects applications that pass a programmatically computed or user-configurable value to the `limit` option without validating it first.

### Patches

This issue is fixed in [body-parser@2.3.0](https://github.com/expressjs/body-parser/releases/tag/v2.3.0) and [body-parser@1.20.6](https://github.com/expressjs/body-parser/releases/tag/v1.20.6) via [#698](https://github.com/expressjs/body-parser/pull/698). After the fix, invalid `limit` values throw a clear error at parser construction time instead of silently disabling enforcement. `null` and `undefined` continue to fall back to the default limit (`100kb`).

### Workarounds

Validate `limit` before passing it to body-parser. For example, parse the value with [`bytes.parse()`](https://github.com/visionmedia/bytes.js) at startup and reject any configuration where it returns `null` or a non-finite number.

### References

- [#698](https://github.com/expressjs/body-parser/pull/698): fix PR - [bytes.js](https://github.com/visionmedia/bytes.js): limit parser

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GHSA-v422-hmwv-36x6 — body-parser vulnerable to denial of service when invalid limit value silently disables size enforcement