Affected: CleanStart: langfuse

Security vulnerability affects the langfuse package. ### Summary `qs.

### Summary

`qs.stringify` throws a `TypeError` when it serializes an object whose own `constructor` property has a truthy, non-callable `isBuffer` member. `utils.isBuffer` duck-types buffers by calling `obj.constructor.isBuffer(obj)` after checking only that the property is truthy, so a value such as `{ constructor: { isBuffer: "x" } }` makes the call throw `TypeError: obj.constructor.isBuffer is not a function`.

### Details

`lib/stringify.js:127` calls `utils.isBuffer` on every non-primitive value it serializes. `utils.isBuffer` (`lib/utils.js:332`) reads `obj.constructor.isBuffer` and invokes it without verifying that it is a function. `constructor` and `isBuffer` are ordinary property names, so any object carrying them as own properties reaches the unchecked call.

Such an object can be built from untrusted input. `qs.parse("x[constructor][isBuffer]=y", { plainObjects: true })` or `{ allowPrototypes: true }` keeps the `constructor` key as an own property (the default parse options drop it), and `JSON.parse("{\"a\":{\"constructor\":{\"isBuffer\":\"x\"}}}")` produces the same shape with no qs option involved. Express 4 with its default `query parser` setting and body-parser with `extended: true` both call `qs.parse` with `allowPrototypes: true`, so on those stacks `req.query` and `req.body` can carry the shape directly.

#### PoC

```js

var qs = require("qs");

qs.stringify(qs.parse("x[constructor][isBuffer]=y", { plainObjects: true }));

qs.stringify…

Affected: npm: qs

### Summary

`qs.stringify()` calls `utils.isBuffer()` on every value it serializes, and `utils.isBuffer()` invokes `obj.constructor.isBuffer(obj)` without checking that it is callable. A value whose own `constructor.isBuffer` is a non-function makes `qs` call a non-callable and throw `TypeError`. Such a value is produced **by `qs.parse` itself** from an untrusted query string when `plainObjects: true` or `allowPrototypes: true` is set, so a pure-`qs` `parse` → `stringify` round-trip — no `JSON.parse` — turns an unauthenticated query string into an uncaught throw.

An attacker-controlled `parse` input reaches the host application's availability asset — via `qs`'s own recommended `plainObjects` mitigation — and triggers an uncaught exception during a `parse` → `stringify` round-trip.

### Details `utils.isBuffer` runs at `lib/stringify.js:127` for every serialized value:

```js if (isNonNullishPrimitive(obj) || utils.isBuffer(obj)) { ... } ```

`utils.isBuffer` (`lib/utils.js:327-333`) invokes `obj.constructor.isBuffer` without verifying it is callable:

```js var isBuffer = function isBuffer(obj) { if (!obj || typeof obj !== 'object') { return false; } return !!(obj.constructor && obj.constructor.isBuffer && obj.constructor.isBuffer(obj)); }; ```

`constructor` and `isBuffer` are ordinary keys. `qs.parse` with `plainObjects: true` or `allowPrototypes: true` keeps them as own properties, so the parsed value carries a non-function `constructor.isBuffer`; `stringify` th…

qs: qs: Denial of Service via improper validation in stringify function qs: qs: Denial of Service via array limit bypass in query string parsing

Affected: Ubuntu:Pro:14.04:LTS: node-qs, Ubuntu:16.04:LTS: node-qs, Ubuntu:18.04:LTS: node-qs, Ubuntu:Pro:20.04:LTS: node-qs, Ubuntu:22.04:LTS: node-qs, Ubuntu:24.04:LTS: node-qs, Ubuntu:26.04:LTS: node-qs

### Summary `qs.stringify` throws a `TypeError` when it serializes an object whose own `constructor` property has a truthy, non-callable `isBuffer` member. `utils.isBuffer` duck-types buffers by calling `obj.constructor.isBuffer(obj)` after checking only that the property is truthy, so a value such as `{ constructor: { isBuffer: "x" } }` makes the call throw `TypeError: obj.constructor.isBuffer is not a function`. ### Details `lib/stringify.js:127` calls `utils.isBuffer` on every non-primitive value it serializes. `utils.isBuffer` (`lib/utils.js:332`) reads `obj.constructor.isBuffer` and invokes it without verifying that it is a function. `constructor` and `isBuffer` are ordinary property names, so any object carrying them as own properties reaches the unchecked call. Such an object can be built from untrusted input. `qs.parse("x[constructor][isBuffer]=y", { plainObjects: true })` or `{ allowPrototypes: true }` keeps the `constructor` key as an own property (the default parse options drop it), and `JSON.parse("{\"a\":{\"constructor\":{\"isBuffer\":\"x\"}}}")` produces the same shape with no qs option involved. Express 4 with its default `query parser` setting and body-parser with `extended: true` both call `qs.parse` with `allowPrototypes: true`, so on those stacks `req.query` and `req.body` can carry the shape directly. #### PoC ```js var qs = require("qs"); qs.stringify(qs.parse("x[constructor][isBuffer]=y", { plainObjects: true })); qs.stringify(JSON.parse("{\"a\":{\"cons…

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Red Hat OpenShift Container Platform ausnutzen, um einen Denial of Service Angriff durchzuführen.