Allocation of Resources Without Limits or Throttling Affecting hackney package, versions >=2.0.0 <4.0.1
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-HEX-HACKNEY-16877830
- published26 May 2026
- disclosed25 May 2026
- creditPJUllrich
Introduced: 25 May 2026
NewCVE-2026-47073 (opens in a new tab)How to fix?
Upgrade hackney to version 4.0.1 or higher.
Overview
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling through the hackney_ws frame and handshake receive paths in the WebSocket client. An attacker can exhaust memory by acting as a hostile WebSocket server and sending a frame with a huge declared length while trickling payload bytes, streaming an upgrade response without the CRLFCRLF terminator, or sending an endless chain of non-final continuation fragments. The vulnerable code buffers frame payloads, fragmented message data, and handshake response bytes without bounds, so a remote peer can drive the client into OOM and crash the process. This can terminate client applications and interrupt WebSocket connections and any work that depends on them.