libp2p is a JavaScript Implementation of libp2p networking stack. Prior to version 16.2.6, an unauthenticated remote peer can exhaust the disk storage of any @libp2p/kad-dht node running in server mode by sending an unbounded stream of PUT_VALUE messages whose keys bypass all content validation. No credentials, no prior relationship, and no protocol deviation beyond a crafted key are required. The victim node's datastore fills until the host disk is exhausted, making the node unavailable. This issue has been patched in version 16.2.6.

Affected: npm: @libp2p/kad-dht

### Summary An unauthenticated remote peer can exhaust the disk storage of any `@libp2p/kad-dht` node running in server mode by sending an unbounded stream of `PUT_VALUE` messages whose keys bypass all content validation. No credentials, no prior relationship, and no protocol deviation beyond a crafted key are required. The victim node's datastore fills until the host disk is exhausted, making the node unavailable.

### Details Two cooperating defects combine to produce the vulnerability. **Defect 1: `verifyRecord` silent early-return (`packages/kad-dht/src/record/validators.ts:19-21`)** ```typescript export async function verifyRecord(validators: Validators, record: Libp2pRecord, options?: AbortOptions): Promise<void> { const key = record.key const keyString = uint8ArrayToString(key) // decode as UTF-8…