tiny-secp256k1 is a tiny secp256k1 native/JS wrapper. Prior to version 1.1.7, a malicious JSON-stringifyable message can be made passing on verify(), when global Buffer is the buffer package. This affects only environments where require('buffer') is the NPM buffer package. Buffer.isBuffer check can be bypassed, resulting in strange objects being accepted as a message, and those messages could trick verify() into returning false-positive true values. This issue has been patched in version 1.1.7.

Affected: npm: tiny-secp256k1

### Summary

A malicious JSON-stringifyable message can be made passing on `verify()`, when global Buffer is [`buffer` package](https://www.npmjs.com/package/buffer)

### Details

This affects only environments where `require('buffer')` is <https://npmjs.com/buffer> E.g.: browser bundles, React Native apps, etc.

`Buffer.isBuffer` check can be bypassed, resulting in strange objects being accepted as `message`, and those messages could trick `verify()` into returning false-positive `true` values

v2.x is unaffected as it verifies input to be an actual `Uint8Array` instance

Such a message can be constructed for any already known message/signature pair There are some restrictions though (also depending on the known message/signature), but not very limiting, see PoC for example

https://github.com/bitcoinjs/tiny-secp256k1/pull/140 is a subtle fix for this

### PoC

This code deliberately doesn't provide `reencode` for now, could be updated later

```js import { randomBytes } from 'crypto' import tiny from 'tiny-secp256k1' // 1.1.6

// Random keypair const privateKey = randomBytes(32) const publicKey = tiny.pointFromScalar(privateKey)

const valid = Buffer.alloc(32).fill(255) // let's sign a static buffer const signature = tiny.sign(valid, privateKey)

// Prevent processing any unverified data by fail-closed throwing function verified(data, signature) { if (!Buffer.isBuffer(data)) data = Buffer.from(data, 'hex') if (!tiny.verify(data, publicKey, signature)) throw new Error('…